An Edmonton man who was serving a life sentence in the death of his sister-in-law and the assault of a cab driver has died in custody. Kenneth Butler, 43, died in the Regional Psychiatric Centre in Saskatoon on Monday. Butler killed his sister-in-law Stephanie Butler, 25, in her south Edmonton home in April 2007 using the lid from a toilet tank, a coat rack, and his boot. Before killing Stephanie he beat a 67-year-old cab driver, leaving him with brain damage. On April 8, 2009, Butler was sentenced to life in prison with no chance of parole for 19 years on the second-degree murder conviction in Stephanie’s death. He was also sentenced to eight years for the assault on the cab driver to be served concurrently with the murder sentence. Butler’s cause of death has not been revealed. Correctional Services of Canada will conduct a review of his death and have notified local police and the coroner.