A fire ripped through an overcrowded retirement home in central Russia overnight, killing 11 vulnerable people as the blaze swept through the small wooden building, investigators said yesterday. The Investigative Committee, which probes major crimes, said it had opened a criminal investigation into possible negligence over the blaze in the Bashkortostan region south of the Ural Mountains. The victims -- seven men and four women -- were between 57 and 83 years old. Different possible causes for the fire were being considered, the official said, including faulty wiring or human error like smoking a cigarette in bed.