Reformed gangster Raymond 'Shrimp Boy' Chow caught in the FBI's net

When Raymond "Shrimp Boy" Chow walked the streets of San Francisco's Chinatown in one of his natty suits, bright pocket square ablaze, he exuded power.

Almost from the moment he arrived from Hong Kong in 1976 at the age of 16, he was a force in the local underworld, working as an enforcer for a local fraternal club called the Hop Sing Tong, shaking down gambling dens and running prostitution rings, according to authorities and his own accounts.

He once told prosecutors he was in charge of all Asian crime in San Francisco, and admitted that he partnered with a leader in an ancient triad group. But after three stints in prison, he said he was going straight.

At 1.65 metres tall, with a shiny bald head and pencil moustache, Chow swaggered. He spoke to youths at risk about the dangers of gang life, became involved in community politics and claimed to be pitching a movie to Hollywood about his life. Social workers believed his transformation, and soon he was honoured by the likes of San Francisco Mayor Edwin Lee, and US Senator Dianne Feinstein.

"All the criminal past I had, I cannot deny that," he said at a press conference in front of City Hall in 2009. "But today I do not represent crime. I do not represent violence and gangs."

That new persona crumbled in recent days when he was arrested in a sweeping federal corruption investigation - one in which State Senator Leland Yee, a San Francisco Democrat, was charged with conspiring to deal firearms for campaign contributions. Two dozen associates were also arrested.