LAS VEGAS -- On Wednesday, investigators were looking through cell phone numbers and a computer hard drive as the investigation into Michael Jackson's death continued.

Those two items were taken from Dr. Conrad Murray's home during a raid Tuesday.

Sources said police believe Murray gave Jackson a powerful sedative that might have killed the singer.

Despite all of the evidence collected, Murray’s attorney said it's the toxicology report that will be the key to this case. The report should be released within a week.

Murray’s office saw the most activities as investigators searched through documents.

Jackson was given the drug Propofol in the hours before his death. It's a drug given through an IV and one where a patient has to be closely monitored and hooked up to an EKG.

Sources said there was no EKG and that Murray may have fallen asleep while Jackson was being given the potent sedative.

Murray’s home was also raided. Investigators spent eight hours between both locations.

“When you’re doing a document search, you’re going through page by page, and it’s very tedious. And everybody inside has the expertise in order to do that and know what they are looking for, but it is very time consuming,” said Michael Flanagan, of the DEA.

Investigators have not said exactly what they are looking for, but 21 documents were seized from Murray's Houston office. They said Murray was cooperative during Tuesday's raid.

They said at this point, he is not a suspect -- just the centerpiece of the investigation.