Benton County Prosecutor's Office

05/20/2026

On Monday, May 11th, Felipe Manjares Jr. was sentenced to 260 months (21 years, 8 months) in prison for the first-degree murder of Michael Castoreno Jr., which he pled guilty to on March 11th. Mr. Manjares shot Mr. Castoreno on December 31st, 2022 at the Columbia Park Apartments in Richland. The Benton County Prosecutor’s Office would like to thank Detective Dustin Richman and the Richland Police Department for their thorough handling of a complex investigation that involved multiple co-defendants. The Benton County Prosecutor’s Office would also like to thank Deputy Prosecutor Tyler Grandgeorge and Former Deputy Prosecutor Julie Long for their hard work on this case, and their dedication to obtaining justice for Mr. Castoreno and his loved ones.

05/06/2026

Today, Abdiel Vargas was sentenced to 23.5 years in prison on two counts of First Degree Assault and one count of Attempted First Degree Burglary from an incident in Prosser, WA in August 2019 in which the defendant attempted to break into an apartment and shot and injured a resident of that apartment. While attempting to flee from the scene, the defendant shot at a responding Prosser Police Officer and struck him in the leg. The Benton County Prosecutor’s Office would like to thank the Regional Special Investigations Unit who conducted an incredibly thorough investigation and to all the law enforcement officers from multiple counties who responded to the scene to assist. The Benton County Prosecutor’s Office would also like to thank Deputy Prosecutors Taylor Anderson, Anita Petra, Brittnie Roehm and Victim/Witness Director Desiree Reynolds for their hard work and dedication in this case.

01/31/2026

This afternoon Judge Jaqueline Shea-Brown found Mason Ashby guilty of Attempted First Degree Murder w/ Notice of Firearm Allegation and Enhancement, Threats to Bomb or Injure Property, and 11 counts of Unlawful Possession of a Firearm in the Second Degree, after a 4 day bench trial in juvenile court.

On September 20, 2025, the Kennewick Police Department was notified of a Tik Tok post depicting a planned school shooting at Kamiakin High School. The report was called in by a TikTok user in Florida who reported the post to the FBI. After identifying the account holder to be associated with the Respondent, law enforcement executed a search warrant of his grandparent’s house where he lived. Law enforcement seized over 20 fi****ms, a second color coded map of Kamiakin High School annotated with notes such as “peak students” and “could shoot through windows”, as well as other documents referencing school shootings. After the search warrant, the respondent’s grandparents reported one firearm missing, which was quickly located by law enforcement. Law enforcement later recovered photos and videos of the Respondent breaking the code on his grandparents safe to access fi****ms in his residence, a video of him walking around Kamiakin High School, and a manifesto he created which he intended to be found after the completion of his attack.

The Benton County Prosecutor’s Office would like to thank the two young men from Punta Gorda, Florida, Anthony Miotto and Ryan Miotto, who saw the post and made the initial report to the FBI. The planned attack was avoided based on their call, and as such this case is the perfect of example how important it is to “see something, say something”.

Additionally, we would like to thank our law enforcement partners from the FBI and Kennewick Police Department, specifically FBI Special Agent Mike Pratt, KPD Detective Alexander Holden, KPD Corporal Kristopher Safranek and others for their combined efforts in conducting a thorough and timely investigation into this case. Lastly, we would like to recognize Prosecuting Attorney Eric Eisinger for his hard work and dedication to assure that the Respondent was prosecuted and held accountable for his actions.

A sentencing hearing will be scheduled for a later date.

01/14/2026

On Friday, January 9, following a two-week jury trial, a Benton County jury returned a guilty verdict against Anthony Martinez Mata for Possession of a Controlled Substance with Intent to Deliver, with an aggravating circumstance finding the offense was committed while in the Benton County Jail. The jury reached its verdict after approximately 40 minutes of deliberation.

The Benton County Prosecutor’s Office thanks the jurors for their service and for their careful consideration of the evidence. We also acknowledge the work of the Tri-City Metro Drug Task Force, the Benton County Sheriff’s Office, and the Benton County Jail for their efforts in the investigation and prosecution of the case.

Finally, we would like to thank Prosecutor Eric Eisinger and Deputy Prosecutor Brittnie Roehm for their hard work and dedication throughout the proceedings.

A tentative sentencing date has been set for January 29, 2026.

12/29/2025

Come join our team!

11/14/2025

Prosecutor Eric Eisinger visited the Tri-Cities Veteran's Resource Expo today. Photos with Ryan Washburn and James Torres with the Benton County Veteran's Court and Kristopher Dahir from the Columbia Valley Veteran's Center. A big thank you to all of the organizations hosting a table at the event to support our local veterans.

09/23/2025

Prosecuting Attorney Eric Eisinger and boxing coach Roy Castillo speak with Blair Day from the Washington Initiative for Boys and Men about Roy’s non-profit organization for high risk youth, Righteous and Chosen Boxing.

Benton County Prosecutor Eric Eisinger envisioned a boxing gym where at-risk youth would get trained and mentored. Into his life stepped Roy Castillo, head o...

09/11/2025

Today we honor the lives lost on September 11th, 2001, and the courage of all the first responders on that day. We will never forget.

08/11/2025

Valentin Sanchez was sentenced today to 90 months in prison for the crime of Unlawful Possession of a Firearm in the First Degree. Mr. Sanchez was found guilty of the offense by a Benton County on May 29th, 2025. The defendant has a prior conviction for Murder in the Second Degree, and is prohibited from owning and/or possessing a firearm. The Benton County Prosecutor’s Office would like to thank the Kennewick Police Department for their diligent and thorough investigation in this matter, specifically Detective Cory McGee, Detective Stefanie Cristelli and former Detective Keith Schwartz. The 90 month sentence was within the standard sentencing range for the offense, which was 77-102 months, based on Sanchez’s prior felony convictions and community custody status at the time of this offense. Following his release, Mr. Sanchez will be required to complete his remaining balance of community custody and register as a firearm offender.

08/05/2025

Join our local law enforcement here in Benton County and celebrate National Night Out, an event that promotes police-community partnership and neighborhood comradery. Kennewick Police Department, Richland WA Police Department, West Richland Police Department and Prosser Police Department all have events going on tonight. Check out both their and their city government pages for details on each event. The Benton County Prosecutor’s Office is very thankful for all the hard work our local law enforcement puts into our community, and this is a great way celebrate and interact with them!