Would a guilty man turn himself in and volunteer for a police line-up? Jon-Adrian Velazquez, convicted of murdering a retired NYPD officer in 1998, is serving 25 years to life in Sing Sing Correctional Facility. But a 10-year Dateline investigation revisits the crime and his case for innocence in the report 'Conviction' airing Sunday, February 12, at 7pm/6c.Feb. 11, 2012