(Reuters) - An off-duty U.S. Army sergeant stationed at the Pentagon has been charged with fatally shooting a Virginia police officer on her first day on the job as she responded to a domestic disturbance at a home outside Washington, authorities said on Sunday.

Ashley Guindon, 28, an officer with the Prince William County Police and a U.S. Marine Corps veteran, died of her wounds after being shot on Saturday evening, a day after she was sworn in as a member of the force, the department said.

Two other officers, Jesse Hempen, 31, and David McKeown, 33, were also shot during the altercation and remained hospitalized, Chief Steve Hudson said during a news conference.

Guindon, Hempen and McKeown were shot at a home they were called to in Lake Ridge, about 15 miles (24 km) southwest of Washington, the county police department said.

Inside the home, police found a woman shot to death and an 11-year-old, who was unharmed, Hudson said.

Army Sergeant Ronald Hamilton, 32, who is stationed at the Pentagon just outside Washington, has been charged in the shooting and was being held without bond, Prince William County Commonwealth Attorney Paul Ebert said.

Hamilton was expected to be arraigned on Monday, Ebert said.

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“It’s a sad day for everyone in this room. It’s a sad day for law enforcement,” Ebert said during the press conference standing next to a photo of Guindon.

Guindon was a graduate of Embry-Riddle Aeronautical University in Daytona Beach, Florida, where she earned a degree in aeronautics. She also served in the Marine Corps Reserve and has family members in law enforcement, according to the county.

The officer was a 2005 graduate of Merrimack High School in New Hampshire, the principal, Kenneth Johnson, said in a statement.

Guindon interned with the department’s forensics services section while she was in graduate school. She graduated in June 2015 from the police academy, but resigned during officer field training for personal reasons. She was hired back about two weeks ago, Hudson said.

“We were struck by her passion to do this job,” Hudson said. “She clearly had a passion to serve others.”

On Sunday, the department posted a photograph of a black ribbon draped over a squad car in honor of Guindon.

“Blessed are the peacemakers, for they will be called children of God,” the post said.

Local media showed a procession of squad cars and officers standing at attention outside of Inova Fairfax Hospital where Guindon and two other officers where brought after they were shot.

On Friday, the department sent a message on Twitter that included a photo of Guindon and a fellow officer after they were sworn in, saying that she would be working her first shifts over the weekend and adding “Be safe!”