It happened around 10:30 p.m. Monday at the Americus Hotel at 6th and Hamilton streets.
Police say the armed suspect was robbing the hotel when the alarm sounded.
He ran off and dropped stolen cash along the way.
He then jumped from the Linden Street bridge into the Jordan Creek below to try to evade police.
However, officers followed the suspect, pulled him from the water and took him into custody.
He was taken to the hospital to be checked out.