A notorious serial killer accused of killing over 40 women and girls in Canada recently died behind bars. Robert Pickton reportedly was killed in a brutal prison beatdown, the Independent reported. The 74-year-old convicted killer was initially hospitalized after sustaining injuries from an alleged attack by a fellow inmate last month at the maximum-security Port-Cartier Institution, nearly 300 miles northeast of Quebec City, CBC reported. The notorious murderer was put in a medically induced coma and on life support in the days leading up to his death. A 51-year-old inmate was held in custody…