Crime scene tape surrounds a Chantilly home Wednesday morning where two people were found dead. (Justin Jouvenal/The Washington Post)

A decorated special agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives and his wife, a popular teacher, were found dead inside their Chantilly home Wednesday in an apparent domestic incident, authorities said.

The bodies of Paul Parisi, 46, and Jannine Parisi, 47, were discovered about 5 a.m. after Fairfax County officers were called to the scene in the 13400 block of Point Pleasant Drive after a report of shots fired, police said.

The couple’s two teenage daughters had been home at the time but fled to a neighbor’s residence. They were unharmed.

Fairfax police declined to identify the aggressor or comment on a motive for the killings.

The deaths shocked family members and neighbors who knew the couple. “Jannine was the sweetest person in the world,” said Adam Finocchi, her brother-in-law. “You couldn’t have picked a worse person for something like this to happen to.”

Paul Parisi had a two-decade career with the ATF and was most recently assigned to the Washington Field Division’s arson and explosives group, according to the bureau. Jannine Parisi was a health and physical education teacher at Franklin Middle School in Chantilly, according to the county school system.

Finocchi said the couple had been married for more than 20 years. They had problems, but Finocchi said he was at a loss to explain what happened inside their single-family home. Finocchi said the couple had lived in Philadelphia before moving to the Washington area, where Parisi wanted to further his career in law enforcement. The pair met at West Chester University in Pennsylvania, Finocchi said.

Parisi won a Department of Justice service award in 2011 for an investigation that led to the prosecution of a Herndon man for setting fire to a Fairfax bar in 2009. He was also honored by the Prince William County Chamber of Commerce for his work this year.

Jannine Parisi had been a teacher since 2005. Former students remembered her as a warm, caring educator who was quick with encouragement and a good listener. The school had grief counselors on hand Wednesday to comfort students and faculty, and the principal called her a “role model” in a letter to parents.

“You could come to her for anything,” said Zina Tambil, 14, who had Parisi as a teacher at Franklin and is now a freshman at Chantilly High School. “She was more than a teacher. We were all her children.”

Neighbors said there were no outward signs of problems. In fact, they said, it was just the opposite. The couple were engaged in their daughters’ lives, Paul Parisi kept their home looking immaculate, and they had recently installed a basketball court and could be seen playing there.

“They were friendly, just like you always hear” in such cases, said Amy Dobbs, a next-door neighbor.

On Wednesday afternoon, a group of ATF agents gathered at the home bowed their heads as Fairfax police removed the pair’s bodies. An American flag flew out front.

Chip Longino, another neighbor, said it is easy these days to live next door to people and never truly know them.

“You are so busy in your own life that you don’t find out about your neighbor’s issues,” Longino said. “You just wave and say ‘Hi.’ ”

Sari Horwitz contributed to this report.