BEIJING, August 19, 2008 (AFP) - Thai boxer and ex-jailbird Amnat Ruenroeng said he felt sorry for his prisoner friends who watched him bow out of the Olympics on Tuesday.

Ruenroeng, who was locked up for a street robbery but released early, faulted the judging as he went down 5-2 to Mongolia's Serdamba Purevdorj in the light flyweight quarter-finals.

'I know everyone in jail will be sad when they saw that,' said the tattooed Amnat, 28.

'I did my best today. I made a lot of hits but didn't get any points, so no matter how hard I tried I still lost.'

The former kick-boxing champion was released on a special pardon for King Bhumibol Adulyadej's birthday last year after being jailed in 2004.

He described his criminal behaviour as a dark period in his life and said he was delighted to be free and fighting again.

'I stole a necklace but then I turned myself in to the police. It was better for me to live in jail at that time,' he said.

'I'm really happy to be here after jail. It's great to have all my fans back.'

Amnat had thought his fighting career was over when he was jailed.

'I didn't think about boxing any more. I cut it out of my mind,' he said.

But then he was persuaded by the head prison guard to join a boxing programme, and won last year's Thai amateur championship while still behind bars.

'I was in prison for two-and-a-half years and released for King Bhumibol Adulyadej's birthday,' he said.

'My boxing and good behaviour were the main reasons (for the early release).'

He said he was happy with his fight against the Mongolian and couldn't understand why he wasn't scoring any points.

'I felt good and my performance was great. It was just as I had expected. But the points didn't go up after the first round,' said Amnat whose tale is a familiar one in Thailand where prisons have a close affinity with boxing.

Last year, convicted female drug dealer Siriporn 'Samson' Taweesuk won her freedom by winning a WBC female light flyweight title fight held at Klong Prem prison, known as the 'Bangkok Hilton.'

The tale had a Hollywood ending when she sold her story to an American film producer.