After weeks of leaks and speculation, the conclusion of the Los Angeles chief medical examiner was announced on Monday by law enforcement officials.
Jackson’s doctor, Conrad Murray, has already admitted administering the drug propofol to the "King of Pop".
Details of his treatment were revealed separately on Monday in documents unsealed by a court in Houston, Texas, where Dr Murray practises.
Court documents showed that Jackson consumed a cocktail of drugs in the hours before he died, the Los Angeles Times reported. According to a newly unsealed affidavit accompanying a search warrant used in the investigation of Jackson’s death, Dr Murray told detectives he gave the "King of Pop" propofol to treat insomnia.
Jackson suffered cardiac arrest and died on June 25 aged 50. Since then, police have investigated his death with a focus on prescription drugs and the role of doctors who treated him, including Dr Murray.
An autopsy report in to Jackons’ death remains sealed while police complete their investigation into the role prescription drugs may have played in his death and the actions of his doctors.
According to court records, Dr Murray told detectives he had been giving Jackson 50 mg of propofol every night for six weeks using an intravenous drip.
Dr Murray told detectives he feared Jackson was forming an addiction and began trying to wean the pop star off the drugs. He lowered the dosage to 25 mg and mixed it with two other sedatives, lorazepam and midazolam. On June 23, two days before Jackson’s death, he administered those two medications and withheld the propofol.
On the morning Jackson died, Dr Murray said, he tried to induce sleep without using propofol, according to the affidavit. He said he gave Jackson valium at 1.30 a.m. When that did not work, he said, he injected lorazepam intravenously at 2 am.
At 3 am, when Jackson was still awake, Murray administered yet another drug, midazolam.
Over the next few hours, Murray said he gave Jackson various drugs. Then at 10:40 am Murray administered 25 mg of propofol after Jackson repeatedly demanded the drug, according to the court records, the Los Angeles Times reported.
At least two doctors gave Jackson propofol in Germany. Dr Murray said Jackson had declined to tell him about what treatment he had received from other doctors.
He said he had seen injection marks on Jackson’s feet and hands. When he asked Jackson about them, the pop star told him he had been given a "cocktail" to help him. In addition to Dr Murray, authorities subpoenaed medical records from several other American doctors.
Dr Murray has already acknowledged obtaining and administering propofol to Jackson the morning that he died. Dr Murray told police he left Jackson alone under the influence of the medication to make telephone calls to his office and family.
He returned to find Jackson was not breathing and performed CPR.
Jackson was declared dead in hospital.