Was overdose reason behind Prince's death?

After number of theories made over pop star Prince's death, it is being claimed that an overdose could have led to the singer's demise.

A law enforcement official has said that the investigators are looking into whether the 57-year-old singer died from a drug overdose and whether a doctor was prescribing him drugs in the weeks before his death, reports E! Online.

The report adds that investigators are also looking at whether a doctor was on the plane that made an emergency landing in Illinois less than a week before the musician was found dead.

Meanwhile, the Chief Deputy of the Carver County Sheriff's Department said that they are continuing to investigate the circumstances of Prince's death.

The 'Purple Rain' hit-maker's plane made an emergency stop in Moline shortly after a live show in Atlanta, roughly a week prior to his death. Officials reportedly said that he was found unconscious on the plane.