With marine, air and ground units, police and emergency personnel were attempting to locate a man who disappeared last night while trying to swim the width of the dam at Prettyboy Reservoir near Middletown in northern Baltimore County, authorities said.
The man, whose identity was not divulged but who was described as in his 40s, was seen swimming across the reservoir near the dam's face about 9 p.m. by a female friend who called police after he disappeared from view, authorities said.
The man had been drinking, police said.
A police helicopter equipped with a high-intensity searchlight and an infrared unit capable of locating a body - even when it us underwater - continued to search the reservoir hours after darkness, police said.