New details about coming out about Liam Payne's final days.

Payne's girlfriend Kate Cassidy left Argentina on October 12, leading many to wonder why he stayed behind.

A source told The Sun U.K. that his non-immigration visa had expired and he was waiting for it to be renewed.

Before his sudden death, the source claims that the One Direction singer spoke with U.S. embassy officials, who wanted to make sure that he was clean before his visa was renewed.

Due to his drug history, the source said, "They ordered him to do medical tests, see a doctor, do bloodwork and X-rays, and see a psychiatrist and that was all done the first week."

"Liam thought the trip would only last a few days, but because of all the tests he ended up getting stuck there," the insider went on.

Without a renewed non-immigration visa, Liam would not have been able to fly into Miami.

The visa was scheduled to be approved on Friday, two days after Payne's death.

Though drugs were found in his system, the source emphasized, "He was completely clean the Thursday before he died."

They added, "On the weekend at his friend's ranch, he was completely sober."

Sources told ABC News that toxicology results from a partial autopsy showed multiple drugs in Payne's system, including pink cocaine. The drug cocktail is reportedly a combination of methamphetamine, ketamine, MDMA, cocaine, benzodiazepine, crack, and other substances.

Insiders add that an aluminum pipe was found in Payne's hotel room.

ABC News sources say Liam's body will stay in Argentina until the autopsy is complete.