PLANO (CBSDFW.COM) – A decorated Vietnam War hero from Plano is going to prison for a crime he committed decades ago.

Alfred Pick was sentenced by federal judge District Judge Marcia A. Crone to seven years in prison for a mistake he made nearly 40 years ago — buying a fully automatic gun that’s illegal for citizens to own. The rifle was similar to the one Pick had in the Army where he served as a lieutenant.

“This gun was very rare at that time it was rare to see one so he instantly had a connection to it,” said Pick’s attorney Ryne Sandel. “Over the course of his life he and his wife and collected about 14 weapons, many of them were collectors items.”

Pick lived in Plano’s Air Park neighborhood along with other pilots who enjoy a runway right outside their homes. The 70-year-old Vietnam veteran even served as the president of his homeowners association. Thus, when the ATF raided his home last year it came as a shock to friends like Mark Shackelford.

“He’s always been a good person to me,” Shackelford said.

Shackelford learned later that authorities were looking for and seized an M14 rifle that Pick had bought at a Fort Worth gun show in the early eighties.

“He was a gun collector and it was probably the piece de resistance of his collection… he had shown it to me. I’ve never seen it taken it out of the case,” said Shackelford.

Federal prosecutors released more information on Friday shedding light on Pick’s dark past.

According to information presented to the court, Pick had repeatedly been cited for criminal trespass at various area hospitals for his aggressive behavior, involving both verbal and physical abuse of medical staff and impeding staff. The court also heard that police had been called on two prior occasions in 2014 to restaurant parking lots where patrons reported that Pick had been threatening and brandished handguns in encounters with him.

Also, Pick’s daughter reported to Pick had sexually abused her from the time she was 4-years-old until the age of 17, taking nude photographs of her to, as he put it, “chart her growth” and sexually assaulting her.

The court also received evidence that Pick threatened the Federal Magistrate Judge who detained him indicating he would fly his plane with explosives to kill the Judge and ATF agents who investigated his case. Pick also said he would “have taught the Las Vegas shooter a thing or two,” referring to the Oct. 1, 2017 mass shooting.

“Obviously, there was a lot more to the sentence that was received – a sentence that Mr. Pick and his lawyer agreed to – than a single gun with a missing serial number,” said U.S. Attorney Joseph D. Brown. “Although Mr. Pick was a decorated veteran, he would use that status routinely to try to excuse his repeated criminal behavior. This was also not a mental health issue. It became a public safety issue.”

The raid and arrest on Pick’s Plano home came two weeks after his wife of 40 years died of cancer. They were using marijuana, which authorities found and added another criminal charge.

Friends of the vet showed up to support him after he pleaded guilty in a Plano federal courtroom and was sentenced to 87 months in prison by a judge.

“He’s had it all these years never robbed a bank or done anything with it,” said Shackelford. “Somebody that made one mistake and now 50 years later, he’s paying a really big price for it.”

More than 40 years ago, Pick was awarded the military’s third highest honor, the Silver Star, after more than 100 combat missions and for a short time he was a POW.

Factors that his friends and attorney say should have led to a lighter sentence.

“He’s a really remarkable man to be honest,” said Sandel. “I do think it’s unfortunate for a gentleman like Alfred that’s had such an outstanding life to have it mired at the age of 70 by this federal felony.”

“The man is a Silver Star winner, he saved lives, he took care of his wife, he’s been in custody for a year, I would think that when a man turned 70 and is an American hero you don’t destroy the rest of his life for one mistake,” said Shackelford.

Some Vietnam vets in Plano were not as sympathetic.

They said Pick should’ve known better especially since the serial number on the rifle was scratched out.