Paul Walker Death Scene -- Alleged Wreckage Thieves CHARGED with FELONY

The law has come down hard on the guys who allegedly pillaged the Paul Walker crash scene ... they've been charged with 3 crimes.

18-year-old Jameson Witty was caught on video stealing the T-top roof of the Porsche right off the tow truck ... and, as if that wasn't enough of a smoking gun ... he then bragged about the heist by posting pics of the stolen wreckage on Instagram.

The L.A. County District Attorney has just charged Witty and his alleged accomplice, Anthony Janow, with felony grand theft, along with 2 misdemeanors -- destroying evidence and resisting, obstructing and delaying a peace officer.

If convicted, the 2 men face up to 4 years and 6 months behind bars.