DNA evidence linked an Oregon prisoner to at least two of the six serial killings of young women that terrified the San Francisco Bay Area and a city in Nevada four decades ago, investigators say. He is suspected of the other slayings.

The San Mateo district attorney's office charged Rodney Halbower, 66, on Thursday with two counts of murder during the course of rape for the deaths of Paula Baxter, 17, and Veronica Anne Cascio, 18.

Their deaths were among six police say are connected and occurred between January and April 1976 in California and Nevada. Five of the bodies were found in the suburbs immediately south of San Francisco, including one near Gypsy Hill Road, giving the killings their nickname. A sixth body was found in Reno.

DNA evidence linking Halbower to both killings was found on Baxter and Cascio, San Mateo Chief Deputy District Attorney Karen Guidotti said.

"Based on the forensic links between a number of the cases, the time frame of the murders, and the methods used by the offender to commit these crimes, investigators are confident all the crimes were committed by the same offender," The FBI said in a statement in March after a Gypsy Hill Task Force was created to revisit the cold case using DNA technology.

Halbower denied involvement in any of the killings in a jailhouse interview with a local television station.

"I'm confused, and I want some answers," he told KGO-TV (http://abc7ne.ws/1yY0UkQ ). "I don't know anything. No knowledge about this."

Halbower submitted a DNA sample when he was transferred from a Nevada prison to Oregon State Prison in November 2013. At the time, Halbower was being paroled in Nevada after serving a sentence for the 1975 rape of a blackjack dealer, which occurred two months before the body of University of Nevada-Reno student Michelle Mitchell, 19, was found.

He escaped from the Nevada prison in 1986 and committed a string of violent crimes in Oregon before he was recaptured. He was serving a sentence in Oregon for attempted murder, assault and robbery when he was extradited to Redwood City and charged with the two murders.

A woman who was convicted in 1980 of killing Mitchell and spent more than 30 years in a Nevada prison was granted a new trial that is scheduled for July and ordered released on her own recognizance in September.

The public defender for Cathy Woods, 64, presented evidence that the DNA on a cigarette butt in the garage where Mitchell's body was found matches that of Halbower.

He is scheduled to enter a plea in Redwood City on Monday.

The brother of one of the Gypsy Hill victims traveled 90 miles from Modesto to attend Halbower's court hearing Thursday. John Blackwell, 56, is the older brother of Tanya Blackwell, the 14-year-old girl whose body was found near the road that gave the killings their name.

He told reporters he attended the hearing to show solidarity with other victims' families, even though Halbower hasn't been charged in his sister's death.

"I feel happy for the families, and I feel some closure," he said. "Some closure is better than no closure."