"He was found unresponsive in a residence," a Los Angeles County coroner's spokesman said. "Paramedics responded and he was pronounced dead."

The former child star began his career aged 12, playing the boy at the centre of 1994 mafia drama The Client.

Renfro had little acting experience when he won the role alongside Susan Sarandon and Tommy Lee Jones.

He went on to star in childhood drama The Cure and played Huck Finn in boyhood adventure Tom and Huck, both in 1995.

In Sleepers the following year, he appeared as the young version of the character played by Brad Pitt.

After that, he took a lead role in controversial teen drama Bully in 2001 and featured in Ghost World with Scarlett Johansson.

He had just finished filming The Informers, an adaptation of the Bret Easton Ellis novel, with Winona Ryder and Billy Bob Thornton.

The film's producer Marco Weber said: "Brad was an exceptionally talented young actor and our time spent with him was thoroughly enjoyable." In 1998, he was charged with cocaine and marijuana possession and avoided jail time with a plea bargain.

In January 2001, he was put on probation and ordered to pay $4,000 (£2,000) for repairs to a 45-foot yacht he and a friend tried to steal in Florida.

Four months later, he was arrested for under-age drinking, violating his probation, and was ordered to undergo alcohol rehabilitation.

In 2005, he was charged with driving under the influence and two counts of driving with a suspended licence, leading to 10 days in jail and 18 months of alcohol education classes.

In a separate incident the same year, he was charged with attempting to possess heroin, resulting in entry to a drug rehabilitation programme.

Renfro's lawyer Richard Kaplan told the Associated Press (AP) news agency: "He was working hard on his sobriety. He was doing well. He was a nice person."

Craig Harvey, chief investigator for the Los Angeles County coroner's office, told AP that Renfro had reportedly been drinking with friends the evening before his death.

An autopsy could be carried out as early as Wednesday, he said.

The actor's body was found at home at 0900 Pacific time (1700 GMT) on Monday, coroner's spokesman Ed Winter told the Reuters news agency.

But Renfro was also well-known for his personal problems.