Two teenagers accused of "setting a trap" to murder a 16-year-old boy as he rode his bike in Dorchester were ordered held without bail during a tense arraignment hearing Monday morning.

Assistant District Attorney Jennifer Hickman told a courtroom packed with emotional family members of both the victim and his accused murderers that Dushawn Taylor-Gennis, 16, and Raeshawn Moody, 14, planned the shooting of Jonathan Dos Santos before gunning him down.

Surveillance footage shows Dos Santos biking down Fuller Street in Dorchester just before 8 p.m. on Wednesday, reportedly on his way to visit his aunt and uncle. That same footage shows the two other teenage boys moments later hanging out near the Fuller Street Market, laughing and talking on the cell phones. 

About 10 minutes later, the boys are seen splitting up. Prosecutors say that's when they sprung their trap.

One teen stayed near the Fuller Market while the other crouched out of view across the street, said prosecutors. The teen that remained in front of the Fuller Market is seen on the footage flagging Dos Santos down as he rode by on his bike.

Prosecutors said that when Dos Santos stopped his bike, the boy across the street rose up and fired five shots, one fatally striking Dos Santos in the neck.

Police said that the three boys knew each other, but the motive was not yet clear.

Cherry said Dos Santos started asking him for rides home from Boston International High School recently because kids were pressuring him to join a gang, but Dos Santos wanted no part of the action.

“He was trying to stay low and stay out of trouble,” Cherry said. “He was obviously worried about things going on in the neighborhood. There are plenty of kids in every city who don’t go to school because they’ll encounter dangerous gang situations.”

Boston Police and the prosecutors have not issued a statement on the motive behind the shooting. But the death has shaken the community. He is the second kid to be shot in Dorchester while riding a bike down a street in daylight this summer. Divan Silva, 7, was shot as he rode his bike on Bowdoin Street on May 26.

“It disturbs me to the deepest parts of my soul,” Cherry said. “I grew up in this same neighborhood and saw my fair share. But the street rules of engagement have been tossed out if we have a 16-year-old and a 14-year-old carrying guns and shooting other kids.”

Mayor Marty Walsh praised the Boston Police for swiftly apprehending the two suspects and thanked the community for their efforts and input.

“This is a tragedy. We lost a 16-year-old, and two other juveniles were arrested," Walsh said. "Three families' lives have been shattered, and we're talking about young kids having guns."