OAKLAND (KPIX 5) – An East Bay man and convicted felon could face 10 years in federal prison because of what he posted on Facebook.

The pictures give a whole new meaning to the phrase smoking gun. Authorities said Zack Mapp posed with three semiautomatic weapons: a pistol and two rifles. The caption says in part: “Ridin around with fed cases.”

Mapp posted it himself on Facebook, one of at least eight photos that authorities with the Bureau of Alcohol, Tobacco and Firearms discovered, and used to arrest him.

“If you’re dumb enough to put incriminating evidence on your social media page that’s available publicly, well, shame on you,” said KPIX 5 security analyst Jeff Harp.

Harp says authorities routinely use social media to dig up evidence on suspects.

“I can guarantee you that every single investigator today, if they’re worth anything, the very first thing they do is go to a social media platform,” Harp said.

Perhaps the most incriminating evidence came after authorities got a warrant for Mapp’s private messages. They discovered a video of Mapp with a gun, its serial number visible.

Court records said, “The serial number was assigned to a firearm that was reported stolen.”

In another private message, an agent said Mapp appeared to indicate that he “recently robbed or burglarized someone and stole a firearm.”

Combined, the evidence was enough to arrest Mapp. Authorities raided his home on 94th Avenue in East Oakland in late June.

Authorities said Mapp did have a gun in his room when he was arrested.

As of Wednesday night, Mapp is being detained in an Oakland jail on weapons charges.