Augusta police secure the entrance to the Edmund S. Muskie Federal Building at 40 Western Ave. in Augusta after a shooting inside the building April 20. Police and investigators at the scene said a man with a knife was shot by a security guard who was screening visitors to the building. Andy Molloy/Kennebec Journal file

An Augusta man who allegedly held a knife near the throat of a security officer at the Edmund S. Muskie Federal Building pleaded guilty Tuesday to assaulting a federal official.

Derik Broox Wight, 41, entered the plea at the U.S. District Court in Bangor Tuesday morning, according to U.S. Attorney Darcie N. McElwee. He will be sentenced following an investigation by the U.S. Probation Office.

Wight faces up to 20 years in prison and a $250,000 fine.

The charge stems from an April 20 incident during which Wight allegedly pulled out a knife as he approached an officer  who was screening people at the entrance to the building at 40 Western Ave. The officer was contracted by the U.S. Department of Homeland Security’s Federal Protective Service.

Wight then pinned the officer against the wall, held the knife near the officer’s throat and then moved the weapon out by his side, near his hip, according to an affidavit by FBI Special Agent Timothy Theriault. Another security officer then pointed his gun at Wight and fired a single shot that struck Wight, Theriault wrote.

Filings by the prosecutor in the case, McElwee, later indicated that Wight had entered the vestibule area of the federal building on three occasions in quick succession that day and made small talk with security guards, leaving each time without incident before returning with a knife. Wight also allegedly indicated verbally that he didn’t believe the other officer would shoot him, according to McElwee.

He did, and Wight released his hold on the guard, dropped the knife and fell to the ground, where security officers secured the site then began rendering first aid to Wight.

Wight was arrested and taken to MaineGeneral Medical Center in Augusta for treatment of a gunshot wound, then placed in federal custody.

James S. Nixon, an assistant federal defender assigned by the Office of the Federal Defender to serve as Wight’s attorney, declined to comment on the case or why Wight pleaded guilty Tuesday.

Wight initially pleaded not guilty to the charge in May and was scheduled for a trial in July but the case was continued multiple times. Most recently his trial was scheduled to start with jury selection Oct. 4 before Judge Lance E. Walker in federal court in Bangor, according to court records.

Wight is in the custody of the U.S. Marshals Service.

At the time of the incident the security officer grabbed by Wight was employed by Petronus Security, a subcontractor for Paragon Systems Inc., an entity that contracted with the Federal Protective Service to provide security services at the federal building.

The building houses a post office and several federal offices, including the Internal Revenue Service.

If the case had gone to trial, prosecutors said in court filings they would have offered the testimony of witnesses including the security officers involved, as well as video footage of the incident.