A woman found at the bottom of a Bedford hotel pool was in critical condition Sunday evening, a spokesman for the town’s police and fire departments said. The 40-year-old woman, a guest at the DoubleTree Boston-Bedford Glen hotel, was found at the bottom of the hotel pool just after 7:45 p.m. Sunday, spokesman John Guilfoil said. A bystander, an EMT, gave the woman CPR until firefighters arrived at the hotel’s location, 44 Middlesex Turnpike, Guilfoil said. The woman was taken to a nearby hospital in critical condition. How the woman got to the bottom of the pool remained under investigation Sunday night by Bedford police, Guilfoil said.