The mother and children went inside first, police said. Minutes later, a masked man wearing gloves came through the unlocked door, ordered them into a back room and tied up the teen. The family friend went in next, and the attacker cut him with a sharp object when he did not immediately comply with orders to get on the ground, police said.
The father then went inside and was also assaulted, police said.
The assailant implied he had a gun, but none of the victims saw it.
“The family was terrified, and this appears to be random,” said Fairfax County police spokeswoman Lucy Caldwell. Police think robbery was the motive, she said.
Police said the attacker walked everyone to the family car and ordered them to drive to a nearby ATM to withdraw money.
The man told the father to get into the car trunk and the family friend to drive to a secluded business park area off Innovation Avenue, police said.
There, the man freed all of the victims except the father, who was still in the trunk, police said. The other adults ran and flagged down a bicyclist, who called for help.
At some point, the attacker fled on foot, police said. When the father realized that the assailant was gone, he was able to escape.
The man is described as black, in his 30s and lean. He is about 5 feet 9 inches and wore a dark hat; a dark, baggy sweatsuit; and black athletic shoes, police said.
Neighbors said the Herndon gated apartment complex is home to a diverse group of families and young professionals. Drivers need to enter an access code or use a remote control to open the gates after 6 p.m., according to Nathan Redabaugh, an employee. Neighbors said a gate has been left open for three days.
Neighbors said that the area is safe but that they have heard about more than a few car break-ins. “It’s scary. It makes me feel less secure,” said Ghizlane Nejmaoui, 32. “We generally feel pretty safe here.”