Authorities have determined that the man suspected of fatally shooting three Iranian musicians in their East Williamsburg apartment on Monday was armed with an assault rifle and had 100 rounds of ammunition on him at the time.

Cops have named Raefe Akhbar, 29, as the suspect in the killing of The Yellow Dogs members and brothers Soroush Farazmand, 27, and Arash Farazmand, 28, along with fellow musician and writer Ali Eskandarian, 35; authorities now believe Akhbar, who turned the gun on himself after his rampage, used a .308-caliber assault rifle and was armed with heavy artillery. "He had five magazines and about 100 rounds of ammunition,” NYPD Commissioner Ray Kelly told the Daily News. They reportedly found 81 unfired rounds, some of which were in magazines stashed in a guitar case Akhbar had carried with him.

Authorities are currently investigating how Akhbar, who was residing in the United States on a work visa, obtained the Spanish-made weapon. They believe it was legally purchased in an upstate gun shop sometime before 2006, but the shop has since shut down. Cops are tracing the gun's chain of ownership and say it was never reported stolen.

Akhbar was reportedly angry with the band members after they excluded him from the music scene. He had been kicked out of underground Tehran band The Free Keys after bandmembers accused him of stealing money from them, according to police reports, and early Monday morning cops say he accessed the Maujer Street building in which the Farazmands and Eskandarian resided via neighboring rooftops, shooting through Eskandarian's window before climbing into his apartment.

Another resident, Sasan Sadeghpourosko, 22, was injured, and Free Keys band member Pooya Hosseini fought Akhbar off. Cops say The Yellow Dogs' other members, Koory Mirzeai, 26, and Siavash Karampour, 24, were not home at the time of the shooting; yesterday, they posted a message about the tragedy on the band's Facebook page.