The Boston Police Department reports the arrest Sunday of a 14-year-old they'd been watching as part of an investigation of several alleged gang members.

The teen and Darnel Marve, 24, were arrested around 1:30 p.m. outside the teen's Gaylord Street home.

Police say their investigation into gang activity in the area began to focus on the kid after they saw a video showing him "in possession of what appeared to be two firearms."

On Sunday, officers staked out his home and soon saw Marve exit the house and put something in the trunk of his car. "The juvenile then exited the residence and joined Marve inside the vehicle. Officers made a stop of the vehicle and upon inspection of a backpack that had been placed in the trunk, officers recovered a loaded Taurus .357 caliber revolver."

Marve was charged with unlawful possession of a firearm, unlawful possession of ammunition and unlawfully carrying a loaded firearm. The teen, not named because of his age, was charged as being delinquent for unlawful possession of a firearm and unlawful possession of ammunition, police say.