Goldstein, 36, was a DJ for hire who performed at Hollywood's most exclusive parties. He became a celebrity in his own right with a glamorous lifestyle and high-profile romances, including with Nicole Richie and Mandy Moore.

Paramedics had to break down the door to his Manhattan apartment before they found his body at about 5:20 p.m., a law enforcement official told The Associated Press on condition of anonymity. There was no evidence of foul play, the official said.

Goldstein had talked openly about past addictions to crack cocaine, Ecstasy and other drugs, but he claimed he had been drug-free for years.

Authorities will need to conduct toxicology tests, expected to take weeks, to determine what killed him, a medical examiner's office spokeswoman said Saturday.

An autopsy Saturday was inconclusive, said the spokeswoman, Ellen Borakove.

A law enforcement official told The Associated Press that police found a crack pipe and prescription pills in the apartment where they discovered DJ AM's body Friday evening. The official spoke to The Associated Press on condition of anonymity because the investigation was ongoing.

A source close to Richie told FOXNews.com that she is "shocked" and understandably devastated over ex-fiance Adam's passing.

"When they were together, Adam and Nicole, they were very cool, very good, happy, and upbeat," the source said.

"She is incredibly affected by this. They had such a close relationship for so long," the source said. "Even though they're not together anymore, they had a close relationship, and were friends. They were in touch as friends but didn't really see each other."

Goldstein died nearly a year after surviving a South Carolina plane crash that killed four people and seriously injured rock musician Travis Barker.

"This comes as a complete shock. I will miss him forever. He was a great friend to me," DJ AM's friend, actor Simon Rex, who was at his welcome home party after the tragic plane crash, told FOXNews.com.

In September of 2008, Goldstein and Barker were seriously burned escaping the plane crash. The pair had planned to perform together for the first time since the crash at an event in Los Angeles on New Year's Eve.

A friend of DJ AM told FOXNews.com that Goldstien "has been spiraling out of control since the plane crash. He was taking so many painkillers for his injuries, he slowly got hooked on them.

"About 7 years ago he went through major drug addictions, and he worked so hard, and successfully kicked the habit. He was terrified to take any of the meds the doctors prescribed him after the crash, but the pain was so bad," the friend said. "Adam took them, and the need for the drugs grew, and now here we are. It's terrible that no one was able to stop him soon enough, but it just happened so fast."