Bethesda Man Found Not Criminally Responsible For Killing Stepfather

BETHESDA, MD — A Montgomery County judge on Monday found Sergio Koyangbo, 21, of Bethesda guilty but not criminally responsible for the 2022 stabbing death of his stepfather, 46-year-old David Beasley, according to the Montgomery County State’s Attorney’s Office.

The state attorney’s office challenged a not criminally responsible finding by a state expert in December 2022 and retained a leading forensic psychiatrist in Maryland to conduct an independent evaluation of the defendant. That doctor, however, came to the same not criminally responsible finding, the state's attorney's office said.

Not criminally responsible is Maryland’s version of an insanity plea, MoCo 360 reported Tuesday.

In light of the second expert’s opinion, the state's attorney’s office said it decided to concede on the finding of not criminally responsible.

Immediately following Monday’s hearing, Koyangbo was committed to the Maryland Department of Health. He will remain in a medical facility pending future evaluations.

On March 5, 2022, Koyangbo was arrested for the fatal stabbing that happened at a residence in the 5600 block of Lambeth Road in Bethesda, Montgomery County police said. According to charging documents, Beasley’s wife, who is Koyangbo’s mother, said she was with Beasley in their bedroom when Koyangbo entered and confronted Beasley.

Koyangbo accused Beasley of looking at his internet search history. Koyangbo pulled a knife from his pocket and stabbed Beasley in the chest. Koyangbo’s mother then called 911.

Montgomery County Fire and Rescue personnel transported Beasley to an area hospital, where he died from the stabbing injuries, according to charging documents.