Suspect in Cold Hit Sexual Assault Prosecution Takes Own Life

Gregory Vien’s Preliminary Hearing halted when defendant hospitalized after suicide attempt. Suspect succumbs to self-inflicted injuries.

Oakland, CA - Alameda County District Attorney Nancy E. O’Malley announces that the cold case against Defendant Gregory Paul Vien has been halted. The case involved the sexual assault of two women from 1997. Both crimes were solved in 2019 through DNA. The defendant was charged with multiple felony sexual assault charges on November 4, 2019. He was arrested November 5, 2019 and held in Santa Rita Jail. In April, 2020 he was released by the Court due to COVID-19 concerns, over the objection of the District Attorney’s Office.

The Preliminary Hearing began November 12, 2020 in the Rene C. Davidson Courthouse. Both victim-survivors testified in open court with the defendant and his attorney present. The defendant was out of custody. After the victim-survivors’ testimony, the defendant shot himself several times with a nail gun, sustaining significant injuries. On November 19, 2020, Vien died from his self-inflicted injuries.

The case against Livermore resident Gregory Paul Vien alleged two incidents of sexual assault crimes based on attacks against two women in 1997 in the cities of Livermore and Union City. In May 1997, a woman was attacked in Union City as she walked to BART after work. She was dragged into a secluded area where she was sexually assaulted. Union City Police detectives obtained a sample of the suspect’s DNA from the victim’s clothing. In September 1997, a second victim was attacked and sexually assaulted while she was walking near Livermore High School. The Livermore Police Department collected a DNA sample from the crime scene.

Both cases went cold, and the identity of the perpetrator remained unknown. Through good police work, detectives with the Livermore Police Department, working with the Alameda County District Attorney’s Office Cold Case Unit, persisted in the investigation. Twenty-two years later, in 2019, the officers developed additional leads through a genetic genealogical search. Defendant Vien was identified as the prime suspect and collection of his DNA confirmed him as the assailant in both cases.

Both sexual assault survivors courageously testified about the violent crimes in open court. The second victim was scheduled to complete her testimony on November 13th when the court was informed that Mr.Vien was in the hospital following the suicide attempt.

On November 19, 2020, the District Attorney’s Office was informed that the defendant died as a result of his injuries. As such, the case must been dismissed.

“The survivors of these sexual assaults showed great courage in coming to court to face the man who attacked and terrorized them 23 years ago. Both women lived for all these years without knowing who assaulted her or seeing him brought to justice” states DA O’Malley. “The police agencies never stopped investigating these heinous crimes in order to keep the victim-survivors and the communities of Livermore and Union City safe. We applaud their dedication, tenacity and the excellent investigative work that led to the arrest of and charges against Gregory Paul Vien.”

Posted on Nov 20, 2020