AN UPPER DARBY store owner Tased one of two teens who he believed were shoplifting Wednesday night - but the boys were innocent, according to police.

Now, Dollar World owner You Yang, 42, finds himself incriminated by his own surveillance system, which shows the teen he Tased had his hands up and was trying to back away from Yang when he was struck.

"There were no threats to this guy," Upper Darby Police Superintendent Michael Chitwood said. "He made an assumption and his assumption was wrong, based on the facts."

One of the teens' mothers told the Daily News that after Yang used his Taser, he then pulled out a handgun and threatened to shoot the boys. Police said there wasn't enough evidence to prove that, although they found two guns at the store.

Police charged Yang with simple assault, possessing instruments of a crime and related offenses for Tasing the youth.

Diane Ross said her son Nasir Edwards, 15, was one of the two boys whom Yang had unfairly accused of stealing.

Nasir had the task of picking up some pasta for his mother on his way home from hanging out with his 14-year-old friend that evening. With a 9 p.m. curfew, the boys arrived at Dollar World on West Chester Pike near Larchwood Avenue about 8:45 p.m., Ross said.

Nasir's friend picked up a pack of condoms from the front of the store and, as the boys walked around, his friend realized he was a dollar short and asked Nasir to borrow the money, Ross said. But Nasir only had enough to buy the pasta, so his friend put the condoms down on a different shelf.

That's when Yang thought the teen had shoplifted and he retrieved a Taser from behind the counter, Chitwood said.

"You can see him with the Taser pointed toward the 14-year-old's face as the teen backs away," Chitwood said. "Yang eventually fires the Taser, striking him in the upper left arm, and chases them in and out of the aisles."

After that, Ross said, Yang pulled out a silver handgun, pointed it at the kids and asked if they wanted him to shoot them. They then fled, she said.

"Both kids know they saw a gun but they weren't able to give a big description or whatever, because they ran from it," Ross said.

Chitwood said Yang denied pulling a gun and, in interviews with police, said the kids were only able to say that a silver object was pointed at them.

"It probably was the gun, but nobody can identify the gun," Chitwood said.

At the store, police said, they found a fully loaded 9 mm, for which Yang had a concealed-carry permit, along with a 12-gauge shotgun. Authorities confiscated both guns and the Taser.

After running from the store, the boys went to a friend's house nearby, where they called 9-1-1, Ross said. They then met with police near the scene. Ross met her son about an hour later at the police station, she said.

"They were very much shaken up because they were just taking a regular old trip to the store," she said.

Chitwood, who once was voluntarily Tased at a news conference, said he knows the pain the boy went through.

"Being the subject of a Taser hit, I know what it feels like," Chitwood said. "If he would have confronted the kid and thrown them out of the store, that's fine, but he assaulted them and he had absolutely no right to do what he did."

A woman who answered the phone at Dollar World yesterday hung up on a reporter.

Ross said she feels lucky that her son and his friend escaped a dangerous situation relatively unharmed.

"One more problem in his life, and he'd have pulled that trigger and I would have had a whole different night," she said of the store owner.