(St. Nicholas, MN)  --  Mourners are gathered at Saint Nicholas Catholic Cemetery for the burial of Cold Spring Police Officer Tom Decker.  The hearse carrying the body of the slain officer left St. John’s Abbey Church in Collegeville in a long procession of vehicles - many of them law enforcement squad cars.  Hundreds lined the procession route to pay their respects to the 31-year-old Decker, who was shot and killed Thursday night responding to a welfare check call in Cold Spring.  There were plenty of tears when Officer Decker's widow received a folded American flag at the gravesite.  No one has yet been charged in his ambush killing.  Authorities had to release a suspect yesterday because of insufficient evidence.