The head of America's oldest gun maker, Smith & Wesson, has resigned after a local newspaper exposed his past as a convicted armed robber.

It emerged that James Joseph Minder, 74, appointed as chairman just a month ago, spent more than a decade in prison in the 1950s and 1960s and had even attempted a jailbreak. As a convicted felon, he is not allowed to carry a firearm.

Mr Minder's convictions came to light in the Arizona Republic newspaper.

According to the report, he used a sawn-off shotgun to commit eight hold-ups wearing a trademark hat, white scarf and trench coat. The robberies were at a bank, several drugstores, and a jewellery shop in the Detroit area. He was not very successful, and was arrested several times, as well as serving time for his attempted escape from prison.

He committed at least some of the robberies while he was still a student at the University of Michigan. Mr Minder told the paper that he had decided to step down because: "I felt it was the best thing for the company, given the circumstances."

He said he did not disclose his nefarious past to other board members because "nobody asked," insisting that since his release from prison 30 years ago, he has turned his life around.

Smith & Wesson is standing firm behind Mr Minder, who will remain on the board. The company said: "While recognising the serious mistakes in his early life, the board believes that Mr Minder has led an exemplary life for 35 years and has provided tremendous service to the community."

After his release from prison Mr Minder founded a company called Spectrum Human Services, to help special-needs children learn to lead more independent lives.

He also went on to earn degrees in engineering, sociology and history as well as a master's degree in social work.