ARNOLD, Pa.—The owner of a western Pennsylvania convenience store has been charged with selling synthetic marijuana and drug paraphernalia after the business was raided.

State police say they also found an Uzi submachine gun and $50,000 in a safe deposit box after raiding the Arnold Stop-N-Go store owned by 42-year-old Seif Shuman, of Monroeville.

Shuman's attorney, Duke George, says police "believe" his client was involved in illegal activity but "now they have to prove it. Not easy to prove."

Police raided the business in the tiny city of Arnold, about 20 miles northeast of Pittsburgh, on Thursday.

That happened after police say they conducted a year's worth of undercover buys during which they've confiscated $300,000 and 50 pounds of the synthetic marijuana.

Shuman faces a preliminary hearing on Thursday.