PEABODY – The death of a Peabody man who was found lying in his backyard Tuesday has been ruled not suspicious, but authorities still aren’t saying how $80,000 worth of illegal drugs wound up in his home.Stephen E. Brown, 51, of 17 Birch St., West Peabody, was found dead shortly before 6 p.m.”An autopsy was conducted and officials have concluded that foul play is not suspected,” said Steve O’Connell, spokesman for the Essex County District Attorney, on Thursday.Police found $40,000 worth of Oxycontin and nearly $40,000 worth of marijuana inside Brown’s home, O’Connell said.Peabody Police Capt. Dennis Bonaiuto says the investigation into the drugs is ongoing.”We want to find out where the drugs came from,” Bonaiuto said.