Jason S. Miyares
Attorney General of Virginia

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Commonwealth of Virginia
Office of the Attorney General

Jason S. Miyares
Attorney General


202 North 9th Street
Richmond, Virginia 23219
FAX 804-786-1991
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For media inquiries only, contact:  
Victoria LaCivita
(804) 588-2021 
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Attorney General Miyares Announces Life Sentence in First-Degree Murder Charge

RICHMOND, VA – Attorney General Jason Miyares today announced that Bret Cook, a prisoner at Lawrenceville Correctional Center, was sentenced to a life sentence after pleading guilty to the first degree murder of Mark Grethen, another inmate at Lawrenceville.

On August 3, 2021, Grethen was found unresponsive and fatally wounded in his prison cell at the Lawrenceville Correctional Center in Brunswick County, Virginia. A subsequent investigation of surveillance video and DNA analysis conclusively linked Cook to Grethen's murder. The Judge imposed a life sentence for the murder charge and a 5-year suspended sentence on a weapons charge.

"Today's life sentence for first-degree murder demonstrates my office's commitment to combating violent crime throughout the Commonwealth and seeking tough sentences for repeat, violent offenders. My office will continue to partner with law enforcement agencies and Commonwealth's Attorneys' Offices throughout the Commonwealth to improve public safety and benefit all Virginians” said Attorney General Miyares. 

The Brunswick County Commonwealth's Attorney's Office asked the Office of the Attorney General to assist in prosecuting this case.

“I want to thank Attorney General Miyares for partnering with our office to prosecute this very important case. This collaboration resulted in a just outcome,” said Brunswick Commonwealth’s Attorney William R. Blaine, Jr. 

Attorney General Miyares’ Major Crimes and Emerging Threats Section prosecuted the case and asked the Court to impose the maximum sentence of life in prison. 

Cook was previously convicted of malicious wounding, grand larceny, armed robbery, malicious assault, assault by an inmate on an employee, four counts of misdemeanor assault, eluding, and conspiracy/robbery with the use of a gun at the time of the attack. He is currently serving a 21-year sentence.

The Commonwealth made no agreement with the defendant prior to sentencing. This case was investigated by the Special Investigations Unit of the Virginia Department of Corrections and Chief Prosecutor Phillip O. Figura prosecuted the case for the Commonwealth.