The Drug Enforcement Administration has joined the investigation into Michael Jackson's death.

The federal agency is stepping in to help local police take a look at Jackson's doctors and his medications.

Click play to view an interview with David Pack, a music producer who spent time with Jackson, including singing "Jesus Love Me" together, before Jackson's untimely death.

Investigators will try to determine the sources of the drugs prescribed for Jackson to see whether there is a trafficking pattern.

Following his death, allegations emerged that the 50-year-old king of pop had been consuming painkillers, sedatives and anti-depressants.

The DEA can provide resources and experience in investigating drug abuse, illicit drug manufacturers known as "pill mills" and substances local police may not be familiar with.