A Philadelphia woman's fighting spirit helped save her life, the city's top cop said Thursday.

Charles Ramsey told ABC's "Good Morning America" that Carlesha Freeland-Gaither kept struggling with her captor despite being bound. The 22-year-old nursing assistant's resistance, "probably helped keep her alive," he said.

"My understanding is, even after she was in the car and bound, she continued to struggle with this guy," Ramsey said Thursday. "She's got a lot of fight in her."

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Freeland-Gaither is resting at home in Philadelphia after law enforcement agents rescued her Wednesday outside Baltimore and arrested suspect Delvin Barnes, Ramsey said, adding that detectives are giving her time to settle down before completing interviews.

Authorities said Freeland-Gaither was rescued with the help of a GPS tracking device that had been installed on the suspect's vehicle by the used-car dealership that sold it to him. Iinvestigators read the dealership's name on a traffic-camera image of the car and asked the dealership to turn on the car's GPS and provide the vehicle's location. Police said the dealership routinely puts GPS devices on its vehicles so they can be easily located and repossessed if the owner falls behind on the payments.

Freeland-Gaither, who disappeared Sunday night, had some injuries but was generally doing fine, police said. Her 37-year-old alleged abductor is being held on an unrelated Virginia warrant alleging attempted murder, assault and malicious injury with acid, explosives or fire. Court records show he is from Charles City, near Richmond.

Baltimore County State's Attorney Scott Shellenberger said Barnes will appear by video at 1 p.m. Thursday in General District Court in Towson. Barnes is at the county jail after being turned over to Maryland State Police.

Carlesha Freeland-Gaither's relieved relatives, meanwhile, said they brought her back to her mother's home in the city after reuniting late Wednesday at a Maryland hospital.

Law enforcement agents spotted Freeland-Gaither and Barnes on Wednesday in a car with a broken-out back window in Jessup, Maryland. They arrested Barnes after he stepped out of the car.

Keisha Gaither, who a day earlier had sobbed as she pleaded for the safe return of her kidnapped daughter, was smiling as she stood before the microphone at a news conference in Philadelphia late Wednesday.

"I'm taking my baby home," she said. "Thank you. Thank you so much."

Authorities said there was no indication Freeland-Gaither and the man, who used to live in Philadelphia, knew each other.

"No one else is in danger right now because we got a very dangerous predator off the streets," Police Commissioner Charles Ramsey said.

Authorities credited hard work by law enforcement agents in finding Freeland-Gaither. Bureau of Alcohol, Tobacco, Firearms and Explosives agents had received information from Richmond, Virginia, to be on the lookout for a vehicle that might have been involved in the abduction, said Tim Jones, resident agent in charge with the ATF in Lanham, Maryland.

ATF agents found the vehicle, which had its rear window kicked out, late Wednesday afternoon on a road in Jessup, he said. A witness to Freeland-Gaither's abduction Sunday night had said she kicked out some of the car's windows before the car sped off.

Freeland-Gaither had been last seen on surveillance video being grabbed by a man and pulled toward a car Sunday night as she struggled to get away in Philadelphia's Germantown neighborhood.

Police and federal authorities had released a stream of images over the past two days from surveillance cameras in Maryland and from a Philadelphia supermarket hours before the abduction.

The video showed a man in a knit cap and dark coat walking down an aisle of a store and using a self-checkout station. A timestamp indicated the video was recorded eight hours before Freeland-Gaither disappeared.

A witness called 911 at about 9:40 p.m. Sunday and reported seeing a woman identified as Freeland-Gaither screaming for help as she was forced into a dark gray four-door vehicle.

Police said Freeland-Gaither's glasses and cellphone were dropped on the street, near piles of broken auto glass.

The witness said Freeland-Gaither — described by her parents as easygoing until she's threatened — had broken the car's rear side windows.

Freeland-Gaither, a nursing assistant, graduated from high school in Maryland and lived with her grandfather in Philadelphia until a couple of months ago, when she moved in with her boyfriend.

The Associated Press contributed to this report.