Does violence follow boxer when they leave the ring?

Alas, one of many among fighting men. And the third in a month. On 1 July, Alexis Arguello, one of the game's true superstars, a fighter-turned-politician from Nicaragua, who won and never lost three world titles, was found dead at his home with a self-inflicted gunshot wound to the chest. He was 57.

Ten days later, another ex-world champion, the Canadian Arturo Gatti, once described as the world's most exciting fighter, died while on a family holiday in Brazil, His wife was arrested on suspicion of strangling him with a strap from her handbag but on Friday police released her after it had been established that the 33-year-old Gatti hanged himself.

What is it about boxing that it lends itself to such untimely deaths, through accidents, suicide or homicide? Victims like Oscar Bonavena, the Argentinian who battled Muhammad Ali, shot dead at 33 outside a Nevada brothel in 1976; Trevor Berbick, 52, the last man to fight – and beat – Ali, killed with a crowbar in a church courtyard in Jamaica in 2006; and in London two years ago, the former British and ABA heavyweight champion James Oyebola, like Forrest one of the sport's most decent men, killed in a cowardly attack by youths outside the nightclub where he was a bouncer. The 6ft 9in Obeyola, who was 46 and had retired from boxing 11 years previously, had simply asked them to stop smoking. He was shot in the head and died four days later. His murderers have been convicted.

The litany of disaster stretches back to Jack Johnson, the first black world heavyweight champion who died in a car crash in 1946, via Rocky Marciano (plane crash), Randolph Turpin (suicide), Freddie Mills (apparent suicide) and Sonny Liston (unexplained). Ring fatalities, thankfully infrequent, are an occupational hazard but why is it that sport's most brutal business has such a lethal legacy outside the ropes, mostly involving former world champions?

The British promoter Frank Warren is not alone in finding it baffling. "You can't legislate for accidents which happen in all walks of life, but all these deaths are tragic and it does seem a bit above average." Do boxers attract violence because of who they are and what they do? Are they simply in the wrong place at the wrong time? "It's possible, I suppose," says Warren, "but what is worrying is the high number of suicides and I wonder if this is because of depression which may follow the end of their careers when they simply do not know what to do with their lives. Frank Bruno suffered in this way but fortunately he got help."

Freddie Mills (British light-heavyweight, 46) was killed in an allegedly suicide (found shot in his car) but rumoured gangland killing in Soho, 1965. And Randolph Turpin (British middleweight), aged 37, committed suicide near Llandudno, Wales, 1966.