A former police detective in southern England was being held Monday on suspicion of killing his police officer wife, investigators say.Peter Foster, 35, was detained after the body of Detective Constable Heather Cooper, 33, was found in Blackdown Woods, a preserve owned by the National Trust about 4 miles from their home in Haslemere, Surrey, The Daily Telegraph reported. Police said they responded late Sunday to an emergency call from someone concerned about Cooper\'s safety.A supermarket employee told the newspaper he saw Foster shopping Sunday.\"He just seemed perfectly normal,\" the man said. \"He was not behaving out of the ordinary or acting in any way that would cause alarm. I just cannot believe it.\"Foster and Cooper had worked together as detectives with the Surrey police, officials said. He is reported to have started a plumbing business after being laid off two years ago. The couple had two young children. The Sun reported Cooper was on leave from her job because of pregnancy.Foster got a job commendation in 2006 for his part in a child abuse investigation.