More than 30 years have passed since his release from prison. He now works as a part-time cleaner and his tattoos cannot be seen under a short-sleeved shirt.
But the 65-year-old was still determined to remove the tattoos, a mark of his past.
Peter (not his real name) went for his first appointment at Eden Medical Aesthetics clinic last Friday, more than 40 years after he first had the tattoos inked on his upper arms, chest and abdomen.
He is the first of 15 people to have their tattoos removed for free, under The Next Chapter Project, a new initiative by medical aesthetics supplier Absolute MS.
The tattoos on his upper arms depict women, while those on his chest and abdomen depict leopards and a peacock. The former gangster told The Straits Times in Mandarin: "I chose images from a book that the tattoo artist gave me. The other gang members had tattoos too, so I followed suit."
He was in jail twice in his 20s - over 10 years in total - for armed robbery and clashing with rival gangs.
He had considered removing his tattoos previously, but techniques in the past - he heard of some that involved the use of acid - were more painful.
And modern methods using laser were expensive. One session usually costs at least $100 and a person may require several sessions to remove the tattoos, depending on factors such as size and colour.
The social stigma related to people with tattoos still exists, he said. In the past, his main reason for wanting to remove them was a practical one - he always had to keep his shirt on at home as his parents did not know about them.
Three years ago, he started swimming two to three times a week to alleviate his back problems. But he felt embarrassed at the pool. He said: "When people saw my tattoos, they would move away from me or give me weird stares. I now wear a swimshirt to cover them, but I'd much prefer not having to wear it."
At his first tattoo removal session last week, he was given cream to numb the skin areas with tattoos for about 20 minutes. The removal process took about 10 minutes.
He pursed his lips throughout and later rated the pain a "four upon 10", with 10 being the most painful. But he smiled after seeing that his tattoos looked lighter.
Dr Daniel Chang, who did the tattoo removal, said Peter would likely have to return for eight to 10 more sessions. Peter said: "The removal of the tattoo from my tummy area was particularly painful. But I can tolerate it and I'll come back to do the rest."