An Arizona auto dealer charged with killing a California woman in northern Nevada 40 years ago may have killed other women in the late 1970s, Nevada’s attorney general said.

“All evidence points to defendant being a serial killer,” state Attorney General Aaron Ford said in a court filing submitted ahead of Charles Gary Sullivan’s arraignment Tuesday in Reno in the 1979 bludgeoning death of 20-year-old Julia Woodward. Sullivan, 73, pleaded not guilty and is being held without bail.

However, no evidence was described in court and Sullivan’s attorney, David Houston, said in an interview he doesn’t believe DNA evidence that was presented to a grand jury ties Sullivan to Woodward’s killing.

This undated photo provided by the Washoe County Sheriff's Office shows Charles Gary Sullivan, 73, of Flagstaff, Ariz., following his booking on Friday, Nov. 15, 2019, into the Washoe County Jail in Reno, Nev. The auto dealer from Arizona is expected to plead not guilty in Reno in the cold-case killing of a California woman more than 40 years ago. (Washoe County Sheriff's Office via AP)

This undated photo provided by the Washoe County Sheriff's Office shows Charles Gary Sullivan, 73, of Flagstaff, Ariz., following his booking on Friday, Nov. 15, 2019, into the Washoe County Jail in Reno, Nev. The auto dealer from Arizona is expected to plead not guilty in Reno in the cold-case killing of a California woman more than 40 years ago. (Washoe County Sheriff's Office via AP)

“Even if DNA shows he had contact with her, where is the act of murder proved?” Houston asked.

Houston and Sullivan didn’t challenge a no-bail order, and a judge set another hearing for Jan. 30.

Ford said on the courthouse steps in Reno that the long-unsolved cases remain open.

“Evidence may have gone cold, but our tears have never run dry and our quest for justice never ends,” he said.

In the court filing, Ford and prosecutors called Sullivan a suspect in the killing of Jennie Smith, a 17-year-old waitress at a Reno hotel-casino whose body was found in November 1979, and the unsolved disappearance of Linda Taylor, 23, in March 1979.

Sullivan was identified as a person of interest after Smith was reported missing in March 1978. Investigators said she told a friend she was going to buy cocaine from a man named Chuck.

Police determined that Smith and Sullivan knew each other, but Sullivan was not arrested and later moved out of Nevada.

In Taylor’s case, prosecutors say a tip led investigators to Sullivan, who admitted dating Taylor but denied knowing what happened to her. The woman’s body was never found.

Smith’s skeletal remains were discovered in November 1979 off a remote hiking and biking trail outside Reno, not far from where Woodward’s bludgeoned body was found in March 1979.

Woodward, of San Rafael, California, had been last seen by a friend a month earlier at San Francisco International Airport, where she planned to board a flight to the Reno and Lake Tahoe area, authorities said.

Prosecutors said it appeared both Smith and Woodward had their eyes bandaged, their underwear and identification stolen, and were left wearing one shoe.

Prosecutors say DNA evidence found on Woodward’s clothing led to Sullivan, who was convicted of a 2007 sex attack in California.

Houston, the defense attorney, said earlier DNA tests were inconclusive.

Sullivan was arrested Aug. 28 in Prescott, Arizona.

This story has been corrected to say that Charles Gary Sullivan was arrested in Prescott, Arizona.