An 18-year-old suspected of carrying a gun on a school bus has been arrested.

Hillsborough County deputies say a fellow passenger on the bus headed for Brandon Alternative School saw Jamarcus Simms, 18, loading the gun in his lap. The witness texted a relative reporting what he'd seen, and the relative called 911.

The witness continued to send text updates to the 911 caller, which included a description of Simms and where he attempted to hide the gun.

Deputies say Jamarcus Simms had this Smith & Wesson semi-automatic handgun on him when he was on the bus. (Hillsborough County Sheriff's Office)

Deputies stopped the bus and evacuated all seven students. They found the gun, along with a magazine loaded with 12 rounds and a black ski mask.

Deputies later determined that the gun was stolen out of Temple Terrace.

Simms is charged with possession of a firearm on school property, carrying a concealed firearm, and possession of marijuana.