The FBI is working with Philadelphia homicide detectives to review a 2008 shooting linked to former NFL star Marvin Harrison, authorities said last night. The case seemed to have reached a controversial end point last January, when then-District Attorney Lynne Abraham declined to press charges against Harrison, who was accused of wounding two local men, Dwight Dixon and Robert Nixon. Dixon claimed Harrison shot him in the hand after the two tussled on April 29, 2008, near a North Philadelphia garage Harrison owned.