Convicted killer sentenced after helping teens flee WA in Richland murder
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- Valentin Sanchez sentenced to 90 months on a gun charge.
- Sanchez aided fugitives in fleeing state after 2022 Richland murder.
- Multiple arrests, trials and convictions followed Michael Castoreno’s shooting.
A Benton County man linked to a New Year's Eve 2022 murder is headed back to prison on gun charges.
Valentin Dmitri Sanchez, 42, already had been charged with rendering criminal assistance for helping the suspected killers of Michael Castoreno flee the state when he was arrested on a gun charge in September 2023.
Sanchez is not legally able to own firearms due to his lengthy criminal history, which includes a second-degree murder conviction when he was 14 years old.
He was sentenced to 7 1/2 years in prison for unlawful possession of a firearm in Benton County Superior Court on Monday.
Because he is already on community custody for other offenses, he will have to serve out the remainder of that term of probation once released from prison, according to a news release from the Benton County Prosecutor’s Office.
He’s scheduled to be back in court in October for the first-degree rendering criminal assistance charge, a Class B felony.
New Years Eve murder
Castoreno was shot and killed by Felipe Manjarez, now 21, and Rafael Torres Topete, now 19, outside the Columbia Park Apartments in Richland on New Year’s Eve 2022, according to court documents.
Castoreno was visiting the apartment complex when he crossed paths with Manjarez, Torres Topete and other teens about 8 p.m.
Prosecutors said during Torres Topete’s trial that the group was looking for a confrontation that night.
They allegedly asked Castoreno what his gang affiliations was, and when he answered, one teen pulled a gun out and began firing, according to court documents.
Video surveillance showed four shots fired, which are believed to have been from Manjares. Then Torres Topete is believed to have fired two more times. The group then fled, leaving Castoreno for dead.
A police dog search led officers to an apartment that had been tied to a separate investigation into recent robberies in the area.
Manjares and several others involved in the shooting were identified through a photo posted on Instagram from the night of the shooting, in which they were wearing the same clothing as seen on security cameras in the area.
By then the two men had already fled the state with the help of Manjares’ mother, Rosalina Guzman, and her boyfriend, Sanchez.
When contacted by police after Sanchez’s vehicle was identified, he allegedly told investigators he was on the way to Idaho. His car was later found at his father’s home in Caldwell, Idaho.
Manjares fled to Oklahoma with his mother where they were later arrested, according to court documents.
Torres Topete was arrested in the Tri-Cities after an unrelated robbery. He pleaded guilty to first-degree manslaughter in April 2024. He was sentenced to the 12-year maximum term in prison.
Guzman pleaded guilty to first-degree rendering criminal assistance in October 2024, and was sentenced to seven months in jail.
Manjares is still awaiting trial on a charge of premeditated first-degree murder with a special enhancement for use of a deadly weapon.
Prosser murder
Sanchez was convicted of murder when he was 14.
Sanchez, his brother Ricardo, then 18, and Jose Angel Munguia, then 15, approached a Prosser man in July 1997 that had previously offered them rides, intending to rob the man, according to Herald stories at the time.
Their plan was to have Guivi Darbeliani give them a ride into the country, before having him pull over so one of the teens could urinate.
Prosecutors said the Sanchez brothers thought they were just participating in a robbery, but Munguia had other plans. When Darbeliani pulled over, Munguia pulled out a gun.
Instead of letting the man walk away, as they’d planned, Munguia shot him in the head three times. He then allegedly pointed the gun at the Sanchez brothers because they weren’t helping him load the body into the car.
Prosecutors would later reveal Munguia had been planning to kill the man from the beginning.
The body was found days later in an irrigation canal west of Prosser.
Ricardo Sanchez was sentenced to 17 years in prison. Valentin Sanchez pleaded guilty in juvenile court and sentenced to custody until he turned 21, for a total of 7 years.
Munguia was tried as an adult and sentenced to life in prison without the possibility of parole. He was resentenced to 25 years to life in 2015 after a Washington state Supreme Court ruling threw out life without parole sentences for juveniles.
Sanchez made headlines again in 2000 when he and others escaped from the Mission Creek Youth Camp in Belfair.
This story was originally published August 13, 2025 at 5:00 AM.
