Eve Smith, 17, of Kensington, Md. put down flowers and created a makeshift memorial for Olijawon Griffin, who was fatally stabbed at the Woodley Park Metro Station in Washington, D.C. (Marvin Joseph/The Washington Post)

The robbery that led to an 18-year-old’s fatal stabbing on a Metro platform was part of a setup concocted by a group of teens armed with knives and a handgun, authorities say.

According to court documents made available Tuesday, authorities investigating the Nov. 17 death of Olijawon Griffin found a .45-caliber handgun and two knives behind a locker in the Woodley Park Metro station.

The documents are part of the government’s case against Deon Jefferson, Immanuel Swann, Gary Maye and Tyvell Smith, all 17-year-olds from Maryland. They have been charged as adults with armed robbery in the incident that ended with the death of Griffin, of Olney.

All four appeared in D.C. Superior Court on Tuesday in shackles and wearing khaki pants, sweatshirts and tan shower shoes. Authorities have said the teens, along with at least five others, robbed Griffin of a $400 Helly Hansen jacket, an iPhone and a baseball cap near an Exxon gas station in Adams Morgan after luring him with a false claim of drugs for sale.

About 20 minutes later, after Griffin and two friends walked to the Woodley Park station, they saw the group again. Jefferson, the court documents say, was wearing Griffin’s jacket.

A fight between Griffin and his friends and the other group broke out and Griffin was stabbed in his chest as he tried to aid one of his friends, according to authorities. Prosecutors last week charged Chavez Tyrek Myers, 17, of District Heights as an adult in Griffin’s death. He is charged with second-degree murder while armed.

Nine suspects, including two 15-year-olds and two 16-year-olds, have been arrested in the case. The latter four have been charged as juveniles; authorities say they may face charges as adults.

Police say they are searching for a 10th suspect.

According to the charging documents, which are based on interviews with unidentified witnesses — some said to be part of the group that included the suspects — a group of 10 to 12 teenagers, working on a plan hatched by Maye, decided to “set up” Griffin for robbery.

The plan, the documents say, was to pretend they had marijuana to sell in order to separate Griffin from his friends. During a sham deal by the gas station, authorities say, Swann wielded a handgun and a knife; another teen had a second knife, and Griffin was beaten and kicked and then robbed.

During Tuesday’s hearing, attorneys for the teens argued that some of the witnesses’ statements could not be trusted, because they had been arrested in the case. They also argued that it was unclear that any of the teens were armed, because no weapons were found on them. Myers had admitted to wielding a knife, according to court papers, but only in the fight that killed Griffin — and he allegedly claimed self-defense.

Magistrate Judge Karen A. Howze nevertheless ruled that there was enough evidence to keep the teens in jail. They were ordered held ahead of a hearing scheduled for Friday.