The Newtown Middle School teacher whom police arrested on a felony charge for allegedly illegally possessing a pistol while in that school in early April, has resigned his position.

In a June 30 letter of resignation submitted to School Superintendent Joseph V. Erardi, Jr, eighth grade science teacher Jason M. Adams, 46, of Newtown wrote, "At the close of business on June 30, 2016, I irrevocably resign from my employment as a teacher with the Newtown public schools."

Dr Erardi said July 1 that he has accepted the letter of resignation.

Mr Adams did not provide a reason for his resignation in the letter to the school superintendent. An attempt to reach him for comment was unsuccessful.

Of Mr Adams' leaving the school system, his attorney John Maxwell said, "I have no comment on his resignation, nor does he."

Mr Maxwell said Mr Adams has applied for accelerated rehabilitation in his pending case at Danbury Superior Court. Mr Adams is charged with possession of a weapon on school grounds, a Class D felony.

Accelerated rehabilitation is a special form of pretrial probation. In that diversionary program, the defendant does not enter a plea to the charge. If the defendant stays out of trouble with the law for a period specified by a judge, and other conditions are met, the criminal charge is then dismissed.

Mr Adams' case file has been sealed by the court, meaning that the documents in that file are no longer open for public review.

Mr Adams had a court appearance on June 30. His next court appearance is slated for August 16.

On April 22, a pro forma plea of not guilty had been entered in court on behalf of Mr Adams.

After his arrest, Mr Adams was put on paid administrative leave by school officials. He was facing an administrative investigation by the school system.

Mr Adams had worked for the school system for about a decade and reportedly was a popular teacher.

However, the December 14, 2012, shooting incident at Sandy Hook Elementary School, in which 20 first-graders and six educators were killed by a rampaging gunman, has heightened local sensitivity about the issue of guns in schools.

Mr Adams had a .45-caliber semiautomatic pistol loaded with eight rounds of ammunition while inside the school on April 6, according to police. At the time of the incident, Mr Adams held a valid state pistol permit, according to police. However, school policy forbids the possession of a firearm on school property.

Police have said they are confident that security precautions put in place prior to the incident were instrumental in a swift, appropriate response to the event.

Following the incident, the school system issued a statement. It read, "This matter is very serious and troubling. Both the Newtown public school system and the Newtown Police Department took immediate steps to address the matter.

"The teacher was immediately detained by security personnel. The teacher has additionally been placed on administrative leave, pending an administrative investigation," it added.

Mr Adams' possession of a gun was discovered when he happened to bend over and his blazer rose, revealing to two school employees that he had a gun holster attached to his belt. Those employees then notified school security staff of the matter, according to police.

The school has armed personnel authorized to possess firearms in the course of their work, such as the police's school resource officer and school security officers, but Mr Adams was not authorized to have a firearm while in the school, resulting in the criminal charge.