COLIN McLaren's life has been steeped in crime.

As an undercover cop, Colin risked his life to infiltrate Griffith's Calabrian mafia, which was responsible for the death of anti-drug campaigner Donald Mackay.

As a detective with Victoria Police, he investigated the murders of constables Steven Tynan and Damian Eyre in Walsh St, South Yarra.

As a special task force member, he hunted child rapist and killer Mr Cruel, who was never caught.

After two decades immersed in this criminal underbelly, Colin was understandably burnt out.

So he sought refuge in the tranquil Buckland Valley, in northeast Victoria.

It was there, in 2003, he established Villa Gusto, accommodation and restaurant, building much of the property with his own hands, establishing the vegetable garden, tending his chooks, taking yearly tours to his beloved Italy.

And it was from this valley that he started his writing career, with his books and manuscripts forming the basis of some of the Underbelly TV shows.

The valley and villa was the perfect retreat for a man who had given so much of himself to defend the public good. But now that criminal life has caught up with the 57-year-old.

Not in the form of a past mobster bearing a grudge (although he will remain ever-vigilant, with one eye on his back), but in the form of his health.

"In October last year I was in Sicily researching the mafia for my next book when I had a heart attack," says the articulate and gently spoken Colin.

"I should have put myself in hospital, but I didn't trust the Sicilian medical system, because the mafia control it. So I filled myself with aspirin, caught a plane home and surrendered myself to surgeons here."

He ended up having a quintuple bypass and was told to rest for three months, advice which he "stupidly" ignored - only to suffer the consequences, with two further heart attack scares, one recently.

"Even though my dream here hasn't finished, I need to sell Villa Gusto," says Colin, who put the half-hectare award-winning property and business on the market in November. "I'm exhausted. I know, in my heart of hearts, that it's not well because of the stress of my career."

Colin says he was driven to a life of righting wrongs because he grew up on the rough streets of Richmond, with an abusive, violent, drunk father, whom Colin kicked out when he was 14.

"We were dirt poor, relying on charities, but I had a rich upbringing in so far as I learnt a lot, to distinguish good from bad," he says.

"At times things were so desperate I could have easily turned bad, but we never got in trouble with the police."

In 1979, at the age of 24, Colin became a police officer, because they were "there to help when I was young" and he had a "fascination for the bad end of town".

He chose to become a detective and was selected for the covert investigation unit through the '80s and '90s. One of Colin's early undercover jobs was posing as an art dealer in Griffith, ingratiating himself with the mafia, which led to a hitman pursuing him around the globe.

It also led to the publication, in 2009, of his autobiography, Infiltration, which still holds the record as the biggest true-crime seller in Australia. It is now in its sixth reprint and became the basis of one of the Underbelly instalments. He says the Mr Cruel case was his greatest frustration - while they locked up many paedophiles, they still didn't nab the target.

In all this work, he never felt fear, but says it did make him unstable at times and would often lead to a huge emotional crash.

After experiencing one too many crashes, he decided to fulfil his other boyhood dream of running an Italian trattoria.

Villa Gusto is no humble trattoria. A grand villa, it has earned awards for its food and environmental sustainability.

His other great love has been writing. His fifth manuscript - another true-crime effort based on his life - has gone to the publisher. He also continues to write for TV, contributing to the recent series Killing Time, and the next Underbelly instalment about Squizzy Taylor.

Colin says he had grand plans to turn Villa Gusto into a wedding reception centre. However he knows the property's sale is necessary "or I simply won't be around much longer".

"I have had an interesting life - fascinating. I don't know whether I have had too many dull days," he says. "It's been incredibly hard, demanding and stressful.

"I have not amassed a lot of riches, but I have had a rich run."