Photo by: Provided Surveillance video shows a juvenile who University of Illinois police believe stole a bicycle outside of the Electrical and Computer Engineering building on Oct. 12. Image

URBANA — It's not uncommon this time of year for campus police to field call after call about stolen bicycles.

But 40 since the start of the fall semester — and 71 for the year — is more activity than usual for University of Illinois police, who are asking for the public's help identifying four suspects they say were caught in the act on video in the past week.

"We're finding that bike thefts have really picked up lately and a large percentage of our suspects seem to be juveniles," said Detective Jerry Sandage, who is investigating the Oct. 8 and 12 thefts that police have surveillance footage of. "Typically, we're seeing groups of four or five teens that come through campus and find it's easier to just pick up a bike than walk all the way across town."

All told, police say 2015's reported thefts add up to at least $19,468 worth of stolen bicycles. In 2014, 61 bikes worth $19,391 were reported stolen. In 2013, there were 107 thefts of bikes valued at $28,599.

The Oct. 8 theft that was caught on camera took place near the Siebel Center for Computer Science around 4 p.m. Three individuals were recorded messing with bikes on a rack and eventually stealing one, which had an estimated value of $850. Police say the suspects were teens.

On Oct. 12, a juvenile suspect was seen on surveillance video stealing a bike valued at $1,000 outside of the Electrical and Computer Engineering building. The teen was wearing a black Chicago Bulls sweatshirt, acid wash jeans and gray Nike shoes.

All four suspects are black males, police said.

Because of the number of students and bikes on campus, Sandage says thefts are common — especially in August, September and October — but his department works to try to recover as many stolen bicycles as it can. This year, a little more than $2,000 worth have been recovered.

Police say they're unsure whether it's the same group of individuals stealing, but typically the thieves target bikes that aren't properly locked up. To avoid theft, Sandage recommends purchasing a U-lock: "They're more expensive, but it's worth the investment, especially if you have a more expensive bike."

Anyone with information about the thefts is asked to call UI Police at 217-333-1216.