Two days before a 16-year-old high school student was shot dead outside his home in Southeast Washington last year, he was among a group that accosted the suspect and stabbed him in the eye, according to documents filed in D.C. Superior Court last weekend.

The new information on the April 7 killing of Darius Cannon describes for the first time a possible motive in what had been the District’s first slaying of a teenager younger than 18 in more than a year. Authorities arrested a suspect Friday, nine months after the slaying.

Court documents say Dion Redwood, 39, of District Heights was apparently seeking revenge after being attacked in a hallway of an apartment building three doors from where Cannon lived. Police said Redwood had been visiting his child’s mother.

Police have charged him with first-degree murder while armed. He was ordered detained until a preliminary hearing scheduled for Jan. 17 in D.C. Superior Court. The Public Defender Service declined to comment on the case.

Police said in court documents that the stabbing occurred April 5 and that Redwood filed a police report describing three assailants, including one who matched Cannon’s description. A witness told police he heard Redwood yell after the assault, “I’m going to kill all you. . . .

Police said in court papers that they tracked Redwood’s cellphone to the shooting scene in the 2700 block of Langston Place SE. Cannon was shot about 12:30 a.m. on a Sunday while walking home from his girlfriend’s house. Police said Redwood texted another man three minutes before Cannon was killed, asking whether he had seen the “youngins.”

Another witness told police, according to the court papers, that a man shot Cannon, then chased the fleeing teenager and fired again. Cannon collapsed on a sidewalk, police said in the documents, and the shooter stood over him pointing his gun until he “was no longer moving.”

Cannon was the youngest of 14 children, including three sets of twins. His family said he had nothing to do with the drug trade in his neighborhood, though they and friends conceded he had gotten into trouble with authorities. Cannon’s mother and other relatives could not be reached Monday.

At the time of the slaying, Cannon’s mother said she was trying to get her son out of the District to live with his brother in North Carolina, who was studying to be an accountant. The victim had spent a lot of time in a mentoring program run out of Woodland Terrace’s recreation center that helps at-risk children.