EVANSTON, Ill. (CBS) — Police have arrested two men they say used power tools to steal dozens of bikes in north suburban Evanston.

Alerted by an uptick in bike thefts in downtown Evanston, undercover police officers watched Saturday afternoon as two men looked at bikes locked to a rack at Church and Benson and then stole one a block away.

Commander Jay Parrott says detectives arrested 45-year-old Keith Freedman of Chicago’s Albany Park neighborhood, and 43-year-old Albert Sauls of Skokie, after a brief foot chase.

Parrott says the pair used a hand-held rotary saw to cut a $165 titanium bike lock in fifteen seconds.

Detectives found an extra battery and blade on the men.

The pair is believed to be responsible for more than two dozen bike thefts.