For three years, a 61-year-old  retired Detroit police officer has patrolled the streets of a neighborhood that was once propped up by the city's mighty carmakers but is now a mausoleum for vacant homes. With his video camera, he films the criminals who have filtered in: drug dealers working off the stoops of abandoned homes, burglars casing houses still occupied, chop-shop operators dismantling cars. Some people grumble about  methods, but generally criticism is rare. For many residents, this unsanctioned crime fighting is a godsend, a source of hope for the neighborhood after the city closed and consolidated their police precinct, along with several others, as Detroit's revenue and population fell.