By Reuters Staff2 Min ReadKISUMU, Kenya( Reuters)-Kenyan police firing automatic rifles and pistols laid siege to gunmen trying to rob a bank in the western city of Kisumu on Tuesday, foiling a heist but failing to prevent the assailants’ escape after the five-hour confrontation. Pictures of the incident at a branch of Equity Bank showed officers climbing though the bank’s windows with guns drawn to try to subdue the raiders, while outside the bank a crowd gathered, oblivious to the sound of gun