Lowell police found a male body floating in a pool at Lowell High School at about 5:45 p.m. Monday afternoon, police Captain Randall Humphrey said. The body appeared to be that of a teenager, said Deputy Superintendent Arthur Ryan Jr. State Police sent two teams to help Lowell police investigate, David Procopio, a spokesman for the State Police, wrote in an e-mail. Authorities blocked at least three entrances to the school’s Raymond E. Riddick Field House, where the indoor pool is located. Police have not released the victim’s age or name. “We don’t know how or why the individual was in that area,” Ryan said.