Two Boston teenagers charged with gunning down a 16-year-old boy out riding his bike have been held without bail.

Sixteen-year-old Dushawn Taylor-Gennis and an 14-year-old alleged accomplice pleaded not guilty to murder and gun charges at their arraignment Monday. They were in court but kept out of sight. They are charged in the Wednesday killing of Jonathan Dos Santos.

Members of Dos Santos’ family cried as the prosecutor described how 16 year old Dushawn Taylor-Gennis and his 14 year old co-defendant allegedly gunned Dos Santos down last Wednesday as he tried to ride away from them on his bike.

Police say the three knew each other, but the motive remains under investigation. Prosecutors say the suspects "trapped" Dos Santos, who was shot five times.

Defense lawyers asked that the teens be released to their parents, saying their mothers cooperated with police. Moody's lawyer says police have the wrong person.

Juveniles charged with murder in Massachusetts are exposed to the same penalties as adults and their cases are open.

Taylor-Gennis’s attorney Michael Doolin, says his client’s mother, who turned him in, believes he is innocent. Doolin says “The case that’s been lodged against him is one of mistaken identity. We look forward to litigating this case in court.”

Prosecutors say surveillance video footage shows the two teenagers are responsible for the shooting.