Man Who Killed Wife in Substation Parking Lot Sentenced to 25 Year to Life in Prison

A San Diego man who fatally stabbed his estranged wife in front of their two toddler daughters in the parking lot of an Imperial Beach sheriff's substation was sentenced Friday to 25 years to life in prison.

Marvin Dennis Duncan, 60, pleaded guilty in May to first-degree murder.

Shortly after 3:30 p.m. Feb. 6, Duncan pressed an intercom button at a side door at the precinct house on Imperial Beach Boulevard, according to sheriff's homicide Lt. Glenn Giannantonio. When a deputy answered, Duncan, who was holding two girls–aged 17 months and 3 years old–announced he had just killed his spouse, the lieutenant said.

The mortally wounded victim, Duncan's 36-year-old wife, Rocio, was found lying on the ground on the west side of the substation. She died a short time later.

Rocio worked with special needs students at Mar Vista High School.

Prosecutors said Duncan used two different knives in the attack.

The children, who were unharmed, were taken into protective custody.

Elsa Medina spoke during the sentencing hearing, asking Duncan, "How could you rob your children of their mother?"

"In her final days, she lived in fear of you," Medina said.

–City News Service