Roy Tucker is a convict.
To here the prosecution tell it, he is an average man with killer skills. He had learned to fight when his mother died when he was young and his father, a drunk from then on, abandoned him while a teenager. After several years of living on his own, stealing and fighting and carousing as it seemed necessary, he was arrested on a hefty charge and given a chance by the judge to 'serve-or-do-time'.
In the military he was taught how to kill. He learned well, especially as a marksman. His deal was to be in for three years and he did those honorably and successfully, rising to the rank of sergeant before his time came up. He was wounded and earned a Purple Heart near the end of his service and probably would have re-enlisted had he not been talked into making a try for an even better life on the outside.
Life in the civilian world would not be easy for a man with one year of high school, a criminal record, and a tendency to hit first and think later. Finding a job would prove difficult for a time. Eventually he got the chauffeur's job with a car dealer, a man who liked the opportunity to hold Tucker's record over his head. It was a job that would introduce him to the dealer's wife and lead eventually to the dealer's death and prison for Tucker and his new love.
Tucker is suspicious, laconic, brash, and demanding. When pushed a little, he will push back a lot harder to make sure the trouble does not escalate. He is also faithful, truthful, and basically honest. In prison he had a made a friend and decided to stand by that friend no matter what happened.
He had been set up as a patsy before, resulting in his being sent to prison at age 28. Now having served five years in that prison, most in maximum security, for first-degree murder with at least another fifteen ahead of him, he is 33 and just wanting to be left alone to survive.
That is when the offer is handed him. In his heart, he knew he was being set up because he knew what being set up was like. He did not care for it.
He is not the sort of man the conspirators should have chosen.