The University of Notre Dame has presented its 2018 Notre Dame Award to a group of Mexican mothers who have led a tireless, years-long search for missing loved ones.

The volunteer group known as Colectivo Solecito has found clandestine burial pits with the remains of hundreds of crime victims in the Gulf coast state of Veracruz.

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The mother of Luis Arroyo Ruiz, who disappeared in Jan. 2018, wears a pendant with his photograph during a Mass at the site where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

The University of Notre Dame has presented its 2018 Notre Dame Award to a group of Mexican mothers who have led a tireless, years-long search for missing loved ones.

A woman cries during a Mass held in honor of disappeared people and the families in search of them in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, the site where almost 300 human remains were found in clandestine graves. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

He presented the award to the group's members for doing everything from fundraising to tromping the countryside looking for burial pits.

A member of the Solecito Collective, made up people searching for their missing loved ones, looks at the site where the remains of Vicente Octavio Colorado were found, during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. (AP PhotoFelix Marquez)

A member of the Solecito Collective, made up people searching for their missing loved ones, looks at the site where the remains of Vicente Octavio Colorado were found, during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. (AP PhotoFelix Marquez)

Ithan Yarel Torres poses for a portrait wearing a photograph of his missing grandfather, municipal police officer Aureliano Sanchez, at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Veracruz state, Mexico, Monday, Oct. 15, 2018. A Mass was held here Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Ithan Yarel Torres poses for a portrait wearing a photograph of his missing grandfather, municipal police officer Aureliano Sanchez, at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Veracruz state, Mexico, Monday, Oct. 15, 2018. A Mass was held here Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Martha Elba Jimenez, mother of Oscar Jimenez who is missing, places his photo on an altar after a Mass was celebrated at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Martha Elba Jimenez, mother of Oscar Jimenez who is missing, places his photo on an altar after a Mass was celebrated at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Basilia Bonastre, mother of Arturo Figueroa Bonastre, whose remains were found amid hundreds of others in clandestine graves, is consoled by friends during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Basilia Bonastre, mother of Arturo Figueroa Bonastre, whose remains were found amid hundreds of others in clandestine graves, is consoled by friends during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A wooden sign indicates clandestine grave number 104 where almost 300 were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. A Mass was held at this site Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A wooden sign indicates clandestine grave number 104 where almost 300 were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. A Mass was held at this site Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A woman who has a missing relative walks amid clandestine graves, that have since been marked, where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, after a Mass at the site. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A woman who has a missing relative walks amid clandestine graves, that have since been marked, where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, after a Mass at the site. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Notre Dame President Rev. John I. Jenkins participated in a Mass Monday at one of those sites.

The mother of Luis Arroyo Ruiz, who disappeared in Jan. 2018, wears a pendant with his photograph during a Mass at the site where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

The mother of Luis Arroyo Ruiz, who disappeared in Jan. 2018, wears a pendant with his photograph during a Mass at the site where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

He presented the award to the group's members for doing everything from fundraising to tromping the countryside looking for burial pits.

Drug and kidnapping gangs in Mexico frequently use such pits to hide the bodies of their victims.

Due to a lack of modern police procedures, few of the bodies located have been identified so far.

A woman cries during a Mass held in honor of disappeared people and the families in search of them in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, the site where almost 300 human remains were found in clandestine graves. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A woman cries during a Mass held in honor of disappeared people and the families in search of them in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, the site where almost 300 human remains were found in clandestine graves. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A member of the Solecito Collective, made up people searching for their missing loved ones, looks at the site where the remains of Vicente Octavio Colorado were found, during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. (AP PhotoFelix Marquez)

A member of the Solecito Collective, made up people searching for their missing loved ones, looks at the site where the remains of Vicente Octavio Colorado were found, during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. (AP PhotoFelix Marquez)

Ithan Yarel Torres poses for a portrait wearing a photograph of his missing grandfather, municipal police officer Aureliano Sanchez, at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Veracruz state, Mexico, Monday, Oct. 15, 2018. A Mass was held here Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Ithan Yarel Torres poses for a portrait wearing a photograph of his missing grandfather, municipal police officer Aureliano Sanchez, at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Veracruz state, Mexico, Monday, Oct. 15, 2018. A Mass was held here Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Martha Elba Jimenez, mother of Oscar Jimenez who is missing, places his photo on an altar after a Mass was celebrated at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Martha Elba Jimenez, mother of Oscar Jimenez who is missing, places his photo on an altar after a Mass was celebrated at the site where almost 300 human remains were found in clandestine graves in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Basilia Bonastre, mother of Arturo Figueroa Bonastre, whose remains were found amid hundreds of others in clandestine graves, is consoled by friends during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

Basilia Bonastre, mother of Arturo Figueroa Bonastre, whose remains were found amid hundreds of others in clandestine graves, is consoled by friends during a Mass in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A wooden sign indicates clandestine grave number 104 where almost 300 were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. A Mass was held at this site Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A wooden sign indicates clandestine grave number 104 where almost 300 were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018. A Mass was held at this site Monday, one day before the Solecito Collective is to be honored by Notre Dame for its work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A woman who has a missing relative walks amid clandestine graves, that have since been marked, where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, after a Mass at the site. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)

A woman who has a missing relative walks amid clandestine graves, that have since been marked, where almost 300 human remains were found in Colinas de Santa Fe, Mexico, Monday, Oct. 15, 2018, after a Mass at the site. The Mass was held one day before the women's Solecito Collective is honored by Notre Dame University for their work locating the remains of missing people in Veracruz state. The Solecito Collective is made up people searching for their missing loved ones. (AP PhotoFelix Marquez)