Stamford police made a second arrest Tuesday in the fatal shooting of 16-year-old Marcus Hall, who was gunned down back in September 2018.

John Montero-Delossantos, 21, was charged with murder and conspiracy to commit murder. The arrest came just days after 21-year-old Isaias Delacruz faced a judge on those same charges - plus carrying a pistol without a permit.

Delacruz's arraignment was briefly interrupted Friday when his mother stood up and began shouting that her son is innocent and telling him not to say anything.

"This wasn't supposed to happen to me," he said at one point. Delacruz got emotional and had to be calmed down by marshals.

Court documents show police used surveillance footage, witness statements, anonymous tips and ballistics tests to put their case together against both men.

They say on the night of the slaying, the two men told people they were going to Southwood Square to shoot it up. Montero-Delossantos' arrest warrant notes there was an ongoing street feud with people associated with the apartment complex.

Hall, who was a student at Westhill High School, was shot multiple times including in the head and was on life support for a few days before he died.

"We're pretty confident that he was not specifically targeted... that they were going into the area that night with the intent of doing a shooting, but we do not believe they had a specific target," says Lt. Tom Scanlon.

Hall's death rocked his school community. Principal Mike Rinaldi previously spoke about the emotional burden on students there and called for the violence to stop.

"He had a lot of friends. He was loved by a lot of teachers, and right now, we're just going through an awful, awful time," he said.

Police say one witness told them Montero-Delossantos pulled out a gun while hanging out with people and bragged that it had been used to kill Hall.

"It doesn't get much more tragic than this - two young individuals going to an area and conducting such a heinous crime against a young victim like this," says Scanlon.

Montero-Delossantos and Delacruz are both being held on $2.25 million bond.