A sergeant, working a fare evasion detail, noticed a male suspect (known to him as having prior contacts for bike theft) in the station. When the male saw the sergeant, he quickly ducked into the restroom. The sergeant had dispatch check to see if the male had any wants/warrants and discovered that he had a $5,000 warrant for petty theft. Once the male exited the restroom, the sergeant took him into custody for the warrant. He was booked into the San Francisco County Jail for the warrant.