Metropolitan Police patrol outside the Woodley Park Metro Station where a young man was fatally stabbed Saturday night in Washington, D.C.on November 18, 2012. Olijawon Griffin,18 was fatally stabbed in the Woodley Park Metro station after a dispute with teenagers who had robbed him earlier. (Marvin Joseph/The Washington Post)

The four Maryland teenagers charged as adults in last month’s robbery and fatal stabbing of an Olney man in the Woodley Park Metro station must remain in D.C. jail pending trial, a judge ruled Tuesday.

D.C. Superior Court Judge Ronna L. Beck issued her ruling after about three days of evidence from prosecutors, saying she had found probable cause that the four 17-year-olds were responsible for the Nov. 17 robbery and killing of Olijawon Griffin.

None of the four — Deon Jefferson, Immanuel Swann, Gary Maye and Chavez Tyrek Myers — had prior convictions, and were eligible for release on electronic monitoring, Beck said. She nevertheless ordered them held based on evidence, including the Metro security video and witnesses identifying their involvement in the armed robbery and killing of Griffin, 18.

Prosecutors said at least 12 teens, nine who have been arrested, were responsible for the incidents in which Griffin was robbed of a $400 Helly Hansen jacket, iPhone and baseball cap and then attacked on the Metro platform as they headed home.

During Tuesday’s hearing, prosecutors outlined threats that they said the teens had made against Griffin’s mother. Assistant U.S. Attorney Justin Dillon said the teens openly discussed going to Griffin’s home to “do her” as they sat in a holding cell after their arrest.

The teens incorrectly blamed Griffin’s mother for their arrest, Dillon said, and their conversation was relayed to prosecutors by a security officer with the Department of Youth Rehabilitation Services who was watching them. That officer did not identify which teen made the alleged threats, according to Dillon.

Prosecutors plan to elevate the charge against Myers, the only one of the teens charged with murder in Griffin’s death, to first-degree premeditated murder from second-degree, Assistant U.S. Attorney Kevin Flynn said Tuesday.

Security video showed Myers pulling his mask down and stabbing Griffin in his chest as his back was turned during a fight with another teen, Flynn said.

“He aimed directly for Mr. Griffin’s heart,” Flynn said as Myers shook his head. “This was heinous.”

Myers’s attorneys argued that he stabbed Griffin in self-defense, one of the suspects having told police they saw Griffin holding a knife after he was robbed of his jacket in Adams Morgan. But prosecutors said there was no sign that Griffin had a knife when he was stabbed at the Metro station.

Jefferson, Swann and Maye have been charged with armed robbery. Some may later face murder charges, prosecutors said Tuesday.

Additional details about the defendants emerged Tuesday. Eleven days before the attack, according to Flynn, Myers took his SATs, receiving scores that might have allowed him to attend college; Maye allegedly tested positive for PCP after his arrest; Jefferson was allegedly seen in security video taking a wallet from a friend of Griffin’s who was being attacked in the Metro station; and Swann — who wrote the judge asking for leniency so he could finish high school — allegedly wielded a gun during the robbery of Griffin.

The teens’ next hearing is scheduled for Jan. 2. Tyvell Smith, 17, a fifth juvenile charged with armed robbery in the case, is scheduled to appear for his own preliminary hearing on Dec. 10. The four youngest suspects, two 15-year-olds and two 16-year-olds, have been charged as juveniles and are scheduled to stand trial in January.