Correction: An earlier version of the story incorrectly said that the six teenagers had previously been charged as adults. Before the indictment, only four had been charged as adults. This version has been corrected.

Police patrol outside the Woodley Park Metro Station where Olijawon Griffin, 18, was fatally stabbed in November 2012. (Marvin Joseph/The Washington Post)

A D.C. Superior Court grand jury on Wednesday indicted six Maryland teens as adults in the robbery and slaying last year of an 18-year-old Olney man at the Woodley Park Metro station.

Initially, only one teen, Chavez Myers, 17, of District Heights, was charged with first-degree murder in the fatal stabbing of Olijawon Griffin on Nov. 17. The other three had been charged as adults with robbery, and their case was severed from Myers’s in earlier hearings.

But prosecutors worked in recent weeks to link the other five to Griffin’s slaying. The indictment lodges felony murder charges against Muquan Cawthorne, 16, of Mount Rainier; Isaiah Gant, 16, of Hyattsville; Gary Maye, 17, of Hyattsville; Deon Jefferson, 17, of Landover; and Immanuel Swann, 17, of Brentwood.

New details surrounding the attack were also revealed in the indictment, as prosecutors alleged that the teens had conspired to commit robberies in the District on Nov. 16 and 17, robbing people of iPhones and other items. Part of their plan, according to the indictment, was to take a train to the Woodley Park Metro station, walk across the Duke Ellington Bridge and find targets to rob in Adams Morgan.

A hearing on the indictment is scheduled Thursday before Judge Ronna L. Beck.

All but one of the teens charged in Griffin’s killing have been held in the D.C. jail since their arrest. Gant had recently been released on electronic monitoring.

Two other teens were also arrested and charged in Griffin’s attack. Their cases remain in juvenile court.

Authorities have said that at least 12 teens were involved in an altercation at the Woodley Park Metro station just minutes after Griffin was robbed of a $400 Helly Hansen designer jacket, iPhone and baseball cap blocks away at an Exxon station on Columbia Road NW.

Authorities said that after the robbery, Griffin and his friends walked to the Metro station, where they encountered the teens who had robbed Griffin. A fight erupted that resulted in the fatal stabbing, officials said.

At an earlier court hearing, Assistant U.S. Attorney Justin Dillon played a Metro security video that, according to prosecutors, showed a confrontation between the group of attackers and Griffin and his friends on the Metro platform.

In the video, the teens began stomping and kicking one of Griffin’s friends. Griffin yelled at the teens to fight him one-on-one instead of ganging up on him and his friends. As Griffin began swinging, one of the attackers, whom authorities have identified as Myers, stabbed Griffin once in the chest.