COLUMBIA, S.C. (AP) -- A man accused of killing his ex-girlfriend and two men and hiding their bodies in a drainage pipe at a Columbia apartment complex has been sentenced to life in prison. Prison records show 28-year-old Charles Gamble began serving a life sentence Thursday at a maximum security prison in Columbia. WLTX-TV reports Gamble was sentenced Wednesday after pleading guilty to three counts of murder. Gamble has been in jail since his November 2006 arrest. Police said he was on probation for stalking Shirlene Octavia Young-Yarborough, also the mother of his child, when he broke into her apartment, stabbed her and shot two men as they slept. Gamble was also charged with killing Marcus Antonio Wilson and Marquis Mitchell and hiding all three bodies in a drainage ditch.