An Adams Morgan man was sentenced to 7 1/2 years in prison for the fatal stabbing of his brother during an argument in February.

D.C. Superior Court Judge Gerald I. Fisher sentenced Deon Thornton, 21, to prison after Thornton pled guilty to voluntary manslaughter while armed the Feb. 11 fatal stabbing of his brother Derrick, 22, after an argument in the lobby of the apartment building where they lived.

Prosecutors said the men had been drinking alcohol and got into an argument in the apartment they shared in the 2200 block of Champlain St. NW.

Their grandmother tried to break up the fight, authorities said, before Deon Thornton pulled out a knife and stabbed his brother several times in his chest. He also cut one of his grandmother’s fingers.

The incident was captured by security cameras, which showed Thornton stabbing his brother then fleeing the building. Police arrested Thornton later that evening, according to court documents.