A former bouncer already convicted of killing two young women went on trial in England Wednesday on charges of abducting and killing a 13-year-old girl. Levi Bellfield killed Milly Dowler in March 2002 in the apartment he shared with his partner, Emma Mills, and their two children, prosecuting lawyer Brian Altman told a jury. Altman said he would present testimony that Bellfield removed a mattress from the flat the next day and burned it, The Sun reported. Milly\'s body was discovered several months later in Hampshire. Altman said Bellfield had gone to car auctions in the area. Mills was house-sitting for a friend at the time of the killing, Altman said. She later told police Bellfield told her they would have to move and that bedding disappeared with Bellfield saying he had dumped it because their dog had soiled it. Milly disappeared while she was walking home from school. Bellfield was convicted in 2008 of the murders of Marsha McDonnell, 19, and Amelie Delagrange, 22.