OAKLAND -- More than two decades after Patrick Willis sexually assaulted and then killed two women in East Oakland, the 49-year-old was sent to prison for life Friday with no chance of parole.

Willis, who was found guilty of the murders and sexual assaults based largely on DNA evidence, shook his head throughout the sentencing hearing. At one point, Willis said, "I don't even care."

Willis was arrested and charged in 2011 for sexually assaulting and killing Cheryl Walker, 31, and Marsha Gulley, 23. The arrest and charges came after Oakland police were able to connect the ex-con to the killings through DNA samples taken at the time the bodies were found.

The connection came as police began reviewing "cold cases" and running DNA profiles taken from the scene of crimes through state and national databases of DNA profiles taken of defendants convicted of felonies.

The first connection to Willis came in 2003 when his DNA profile in a state database matched a DNA profile taken from semen that was found in Walker's mouth.

Although police had a match, the case was never charged until 2011 when police reopened Gulley's case and matched Willis' DNA profile to a DNA profile of semen found in Gulley's mouth.

With the two matches, police then found similarities between the murders including their location just blocks from where Willis's mother lived. In addition, both women were sexually assaulted ¿and tortured in similar manners and attacked at roughly the same time at night and within 13 days of each other.

Testimony from witnesses who heard women screaming and evidence from DNA experts who could narrow the time frame of when the semen was deposited in the women was also used to show that Willis was the only person who could have killed the women.

Nevertheless, Willis continued to deny involvement in the crimes and his attorney, Thomas Broome, promised an appeal as he continued to defend his client.

"There is no evidence in this case that he killed anybody," Broome said.

Deputy district attorney Annie Saadi, however, said she was happy the jury reached a just verdict and that Willis is off the streets.

"He won't hurt anyone anymore, at least anyone outside of prison," Saadi said.