Deputy coroner Cheryl MacWillie declined to state the cause of death in the original July 7 certificate but further investigation led medical examiner Christopher Rogers to purportedly amend the text to "homicide" on August 31.
"We are all keeping our faith with the police. We want them to do this case properly and put away the man who we feel is responsible for Michael's death," News of the World quoted a Jackson family source as saying.
"We want the authorities though to release details of what happened to Michael in his last few hours. We want the paperwork to come out to show just what drugs were put inside him and what happened in his last few hours alive. Much of the documentation has been kept secret - and we can't understand it. We still feel that there is more than one person responsible for Michael's tragic death," the source added.
Jackson died on June 25 last year from "acute Propofol intoxication" due to an "intra-venous injection by another". His personal doctor Conrad Murray has been at the centre of the probe after he confessed injecting the star with Propofol and other drugs in the hours before his death.