A man who authorities suspect to be the Golden State Killer now faces a dozen counts of murder in California after the state brought four new counts against him Thursday.

Joseph James DeAngelo, 72, was charged with four counts of first-degree murder in connection with four slayings in 1979 and 1981 in Santa Barbara County, District Attorney Joyce Dudley said at a news conference, referring the public to the felony complaint.

"Each count carries multiple allegations," Dudley said. "Each of the four counts carry the potential for life without the possibility of parole or the death sentence."

"Each count carries multiple allegations. Each of the four counts carry the potential for life without the possibility of parole or the death sentence." — Joyce Dudley, Santa Barbara district attorney

Prosecutors say DeAngelo, a former police officer, was one of California’s most elusive serial killers.

DeAngelo has been charged with killing Robert Offerman, 44, an orthopedic surgeon; and Debra Alexandria Manning, 35, a psychologist, in their condominium near Goleta, Calif., in December 1979.

Authorities also suspect DeAngelo killed Greg Sanchez, 27, and his girlfriend Cheri Domingo, 35, on July 27, 1981, inside a home also near Goleta, where Domingo had been house-sitting.

Investigators said DNA from that crime scene was linked to other crimes they believe were committed by the so-called Golden State Killer. Prosecutors also used DNA and a genealogical website to identify DeAngelo.

He has already been charged with eight other murder counts in Sacramento, Ventura and Orange counties.

"Violent cold cases never grow cold for victims or their loved ones," Dudley said. "In fact, most of them spend their lives feverishly seeking answers and desperately hoping for justice."

"Violent cold cases never grow cold for victims or their loved ones. In fact, most of them spend their lives feverishly seeking answers and desperately hoping for justice." — Joyce Dudley, Santa Barbara district attorney

Investigators suspect DeAngelo committed at least a dozen murders and more than 50 rapes across California in the 1970s and '80s.

DeAngelo was arrested last month and remains in Sacramento County Jail.

"The sense of relief is overwhelming and it's wonderful," Debbi Domingo, daughter of Cheri Domingo, told Noozhawk.com, a Santa Barbara County news website. "I've spent over two-thirds of my life wondering if we would ever get answers."

DeAngelo's attorney, Diane Howard, did not immediately respond for comment.

The Associated Press contributed to this report.