The suppliers of the drugs Michael Jackson was allegedly hooked on are to be investigated.

The powerful Drug Enforcement Agency will help police determine who treated Jacko and how he got his hands on a mass of prescription-only medicines.

The probe may lead to the King of Pop's death being at the centre of a future criminal trial.

Any doctor or staff who supplied the singer with a cocktail of powerful painkillers, sedatives and anti-depressants could face prosecution.

Much of the focus will be on the lethal Propofol, or Diprivian - the anaesthetic which may have triggered the singer's heart attack. The methadone-based drug is dubbed "the milk of amnesia" and is used to knock people out before surgery.

Experts have warned that it should only be used by professionals and that an overdose can kill. The white fluid was allegedly found at Jackson's house with another powerful narcotic, Lidocaine, which is used to treat its painful side effects.