Although crime across L.A. is dropping, there is one glaring exception: bicycle thefts, which rose 29% last year. Nearly 2,000 bikes were reported stolen last year -- and authorities believe the actual number of thefts was much higher because so many people don’t report stolen bikes.

LAPD detectives believe the increase is due in part to more people using bikes to get around in some neighborhoods. A Times analysis found the USC campus, downtown L.A. and Venice to be hot spots for bike thefts.

Detectives recently broke up a bicycle theft ring and nabbed two men who swiped bikes downtown and sold them on Craigslist. At the motel of one of the alleged thieves, they said they found bolt cutters, hacksaws and a Mercedes-Benz equipped with a bike rack.

Some bike messengers last month took justice into their own hands when they caught two suspected thieves, teenage boys who attended a local Catholic high school. According to police, the messengers stripped down the teens to their boxer shorts before taking their cellphones, backpacks and clothes.

“They meted out street justice. We don’t condone street justice. They never threatened them. But they made it clear: don’t mess with another person’s property,” Los Angeles Police Lt. Paul Vernon said. “This incident and the arrests are the tip of the iceberg when comes to people stealing bicycles.”

Vernon said the two boys told police they were robbed by about 20 men on bicycles at 6th Street and Grand Avenue about 3 p.m. on Jan. 12. Investigators said they cannot prove the boys were stealing bikes and continue to look for the assailants.