In order to complete a successful hit, contract killers need to bury their feelings or emotions, according to a study that looked into the psychology of novice assassins.

Hired killers who consider themselves strategists or businessman, doing "just a job" as one hitman described it, can convince themselves they are dealing with a target rather than a person, research by a team of criminologists at Birmingham City University revealed.

Here are some examples from a press release from the university exemplifying the study results:

  •  North London teenager Santre Sanchez Gayle offered a classic example of detachment, shooting Gulistan Subasi in March 2010, as she opened the door for a paltry sum of £200. The 15-year-old, later sentenced to a minimum of 20 years for the crime, allowed no time for his victim to be personalized before leaving the scene calmly in a taxi.
  •  By contrast, despite agreeing a £7,000 fee for successfully completing the job, when Orville Wright broke into Theresa Pitkin's flat he lost his nerve and failed to complete the "hit" after engaging his would-be victim in conversation.
  •  A rare example of a female contract killer, Te Rangimaria Ngarimu, murdered Graham Woodhatch in May 1992. She was paid £1,500 (after being promised £7,000) and shot Woodhatch while he was attending the Royal Free Hospital in London. Ngarimu fled to her native New Zealand but returned to Britain to confess to her role in the murder. It remains unknown why a multi-linguistic devout Christian, who had several degrees, with no previous convictions, agreed to the commit the hit.
  •  At 62, Paul Cryne was the second oldest hitman in the study. Cryne had a lucrative lifestyle in Thailand throughout the 1990s, but ran up debts. He seems to have met up with Sharon Birchwood's ex-husband, Graham Birchwood, through the expatriate community and accepted the £30,000 contract to kill Sharon. Cryne flew back to the UK to carry out the murder and it would later emerge that Sharon Birchwood's death would allow her ex-husband to inherit £475,000. Cryne was apprehended after leaving forensic evidence at the scene of the crime and jailed for life.

The study points to Jimmy Moody - henchman for the notorious Richardson gang in 1960s London and later a hired assassin for the IRA - as the ultimate example of a hitman who separated his 'work' from the normality of the rest of his life.

The researchers, leading criminologists Professor David Wilson and Mohammed Rahman, said Moody was a classic example of a 'master' hitman, whose motivation to kill was purely financial. "Moody and the other people in our study show us that when contract killers aren't as successful in switching off their emotions, their jobs tend not to go to plan," said Rahman, according to the press release.

"Moody reframed his victims as targets, seeing getting the job done as a normal business activity. These sorts of killers are akin to 'criminal undertakers', who have given themselves 'special liberty' to get things done in the name of business. The motivation for most people who become hitmen is economic, so the reframing shows their resourcefulness as individuals who want to minimize risk and effort in the pursuit of maximizing profit."

Moody is believed to have carried out contract killings in several major British cities in the 1960s, including for the notorious Richardson gang in London. After escaping from Brixton prison in the company of a senior member of the Provisional IRA, Moody became a hired assassin for the republican paramilitary movement. Despite no political convictions he was described as 'a perfect secret weapon for the IRA', torturing suspected informers before shooting them in the back of the head - known for the 'OBE', or 'one behind the ear'. Moody remained on the run until June 1993, when he himself fell victim to a hit, executed in his favorite pub, The Royal, on the edge of Victoria Park in Hackney.