When Suzanne G. Devlin saw a man nearly twice her size attacking people in the baggage claim area of Dulles International Airport, she did what came naturally. She collared him.

Devlin, the acting Fairfax County police chief, was dropping off her husband at the airport Tuesday morning and was out of uniform and unarmed. But she sprang into action anyway, tackling the man and placing her knees on his spine until airport police arrived.

"He kept saying, 'Get your knees off my back, get your knees off my back,' " Devlin recalled yesterday. "I have bony knees."

Police from the Metropolitan Washington Airports Authority took the man into custody and charged Andrew C. Hython, 45, of the District, with three counts of assault and battery, disorderly conduct, grand larceny and destruction of property. He was being held last night in the Loudoun County jail without bond.

An airport spokesman said Hython is 5 feet 9 inches tall and weighs about 260 pounds. Devlin said she is 5 feet 7 inches and weighs about 140. Devlin's takedown also was captured on surveillance video, which confirmed her role in the incident, spokesman Jonathan Gaffney said.

"We're very grateful to her for her help," Gaffney said. "He's a big guy."

Devlin, currently a finalist to become Fairfax's permanent chief, told almost no one about the incident, and Fairfax police did not publicize it.

The incident started about 7 a.m. in the Airlink valet parking lot outside the main terminal at Dulles. Gaffney said the man jumped into a car and tried to steal it but was blocked. He then climbed out of the car with its keys and ran into the terminal with Airlink parking employees in pursuit, Gaffney said.

The man darted into a restroom near baggage claim area 4, Gaffney said, flushed the car keys, then came out, where he was confronted by the parking employees. That's when the brawl began.

Enter Devlin.

She had accompanied her husband into the terminal for his flight and was headed back to her car when she encountered the ruckus.

The acting chief first thought the loud arguing was friendly, until she saw one man try to run away from the agitator at the center of the scene. "I think he hit four or five people," Devlin said. "He was literally running people down."

"He grabbed one guy and threw him against the wall," Devlin said of the incident playing out before her. The 28-year police veteran stepped into the man's path and politely tried to persuade him to redirect his anger. The man rumbled past her and started attacking someone else.

With another victim on the ground, the man lifted his foot and began stomping on his prone captive. Devlin, 50, then launched herself into the man and tackled him while he was off balance, landed on his back and placed her knees on his spine until airport police arrived.

Devlin "tried to get the guy's attention, but he went past me and jumped on another guy. He threw him on the ground and started stomping him when I grabbed him and threw him on the floor." Because he was in mid-stomp, "I guess I caught him at the right time," Devlin said.

The chief said she began yelling for someone to call 911 as she sat on the man and applied her full weight to his back, then began whispering into his ear to calm down and take deep breaths. She feared that he was under the influence of drugs, and that he would quickly regain strength. Two other men helped hold him down while a woman called for help.

"I suppose many people would look at it as absolute stupidity," Devlin said. "But you just gotta do what you gotta do."

Suzanne G. Devlin tackled a man attacking others at Dulles Airport.