Detectives are analyzing footage from closed circuit television cameras outside of Amy Winehouse's home in North London to determine if the singer went out the Friday night before she died, the Daily Mirror reports.

"There are enough cameras in the area to get a picture of her movements," a source told the UK newspaper.

"It's a painstaking operation which involves going through tens of hours of footage."

Winehouse, 27, was found dead in her North London home on Saturday, July 23.

The singer had spoken to her security guard, Andrew Morris, that Saturday morning around 10 a.m., and told him she wanted to go to sleep. That is believed to be her last conversation.

When Morris went to wake her several hours later, he found her dead.

Police sources told the The Mirror that there were no signs of drugs at the house.

A London drug dealer has recently come forward to claim that he sold Winehouse £1,200 (about US$2,000) worth of crack cocaine and heroin hours before she died.

Tony Azzopardi, 53, was questioned by police on Monday in an attempt to piece together Winehouse's final hours.

When he left the station on Monday afternoon, he had to be restrained after an abusive outburst directed at reporters waiting outside the station, Fox News reported.

The Mirror said Azzopardi was expected to be interviewed again on Tuesday.

"I want Amy's family to know the truth about what happened," Azzopardi told the Mirror. "I want to help them out -- but I'm worried about my safety."

An autopsy was conducted on July 25, but the cause of death won't be determined until the toxicology tests are completed, which could take another two to three weeks.

Unidentified friends of the singer told The Mirror that Winehouse had engaged in "wild drinking" in North London in the days preceding her death -- a claim her family vehemently denies.

Amy's father, Mitch Winehouse, told mourners at her funeral that his daughter had conquered her drug addiction years prior, and had recently decided to stop drinking as well.

"Three years ago, Amy conquered her drug dependency," Mitch Winehouse said in the eulogy, which was excerpted in the Daily Mail. "The doctors said it was impossible but she really did it.  She was trying hard to deal with her drinking and had just completed 3 weeks of abstinence.

"She said, 'Dad I've had enough, I can't stand the look on your and the family's faces anymore.'"

He believes Amy's sudden withdrawal from alcohol contributed to her death.

"Abstinence gave her body such a fright, they thought it was eventually the cause of her death," an unidentified family friend told the Sun.