A public safety alert was issued this week for downtown bike commuters.

Police say there's been a dramatic increase in the number of bike thefts in the area.

Emily Shrock, who depended on her bike for transportation, rode it to church on Sunday, only to find out after services that someone had cut the lock.

"I think a lot of people my age ride bikes, especially with the cultural trail and all the bike racks, and you do the right thing and you come out and it's gone," Schrock said.

More than 100 bike thefts have already been reported along a line from the campus at IUPUI to Massachusetts Avenue.

Police say thieves ride an older model bike and wear a backpack with bolt cutters hidden inside.

"They'll pull up to the bike rack and pretend that they're locking up their own bike," said Sgt. Jeff King. "The bottom of the back pack has a slit and they'll cut the lock."

Police suggest bike owners record the serial number and take a picture of the bike, both of which can be attached to a police report.