1979 Sunnyvale cold case murder of Estella Mena solved through new DNA technology, officials say

SUNNYVALE, Calif. (KGO) -- For over 40 years, no one knew who killed Estella Mena. That changed on Thursday. Police identified Samuel Silva as Mena's murderer.

Mena died at the 400 block of De Guigne Avenue in Sunnyvale. She had been stabbed multiple as Silva was trying to sexually assault her. At that time, there were no leads pointing to Silva. Through new DNA evidence and genealogy, they linked Silva to her death.

"We don't forget the victims," said Deputy District Attorney Robert Baker. "We don't forget the families and friends of those victims who still want justice."

Authorities believed Silva fled to Colorado after her death. He died in prison in 2008 while serving a federal gun charge. They say he had a lengthy criminal history, including attempted murder, rape and assault with a deadly weapon. Investigators say Mena met Silva while working at Great America. Baker says new technology made them solve this case.

MORE: DNA evidence links NorCal man to 1983 killing of North Bay woman, detectives say

An arrest has been made in a cold case murder of Noelle Russo that happened 40 years ago outside Rohnert Park.

"No matter how many years -- 10, 20, 50 years -- we want to get justice for those people," Baker said. "The advent of forensic genealogy allows us to be proactive. It allows us to have a name and person behind a profile without having to wait around."

Now, Santa Clara County is taking a step further by launching a new hotline: (408) 792-2466. The hotline can be used to submit anonymous tips about cold cases. Experts think this will help solve more cases.

"It could be the most seemingly insignificant piece of information that allows those investigators to connect the dots and finally get the answers, you know, solve the case," said Kendall Mills with Season of Justice, a non-profit focused on solving cold cases. "You might not think that red car was significant back then, or you may remember being in that parking lot that one time. Human provided detail can go a long way."

Since 2018, Santa Clara has solved 16 cold case murders and 10 sexual assault cases. As technology improves, they hope to solve more.

"Every day an unknown murder victim is given a face and a name through the use of genealogy," Baker said. "We will keep going until we solve as many cases as we can."

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