This story has been updated.

A man charged with stabbing his brother to death in Adams Morgan Friday night also shared an apartment with him, according to charging documents.

Deon Thornton, 21, has been arrested and charged with second degree murder after allegedly stabbing his brother, Derrick Thornton, 22, multiple times in the lobby of the Adams Morgan apartment building they both lived in.

D.C. police say they have surveillance video that shows another man was trying to break up a verbal fight between the two brothers in the lobby of the apartment building at 2207 Champlain St. NW. Deon Thornton then threw the man aside and allegedly stabbed his brother repeatedly. The video also shows Derrick Thornton trying to protect himself with his hands, according to police.

When police arrived on the scene at about 7:40 p.m., they discovered Derrick Thornton on the steps of the building at 2207 Champlain St. NW. He was taken to George Washington University Hospital, where he was pronounced dead at 8:59 p.m. from his wounds, including one to the heart.

A call came to Prince George's County Police at about 10:45 p.m. that Deon Thornton was on the way to a house in the county. Police caught up with Deon Thornton there, who told police that "he stabbed his brother a few times during the altercation but was not sure if his brother was alive," according to charging documents. By that point, Derrick Thornton was already dead.

Deon Thornton was arrested and brought back to D.C. A preliminary hearing in the case has been set for Feb. 23.

Thornton Charging Docs