Federal agents in Pittsburgh on Wednesday arrested the man police believe killed Christina Carlin-Kraft, the  36-year-old model who was strangled inside her Ardmore apartment last week.

"This arrest comes on the day of Christina's funeral. She was surrounded by her family and friends today," said Montgomery County District Attorney Kevin R. Steele.

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Steele wouldn't comment on a motive in the killing but said there was no indication that the two had met before the night of her violent death.

Jonathan Wesley Harris, 30, was taken into custody by U.S. marshals just before 4 p.m. Wednesday as he stepped off a commuter bus, Steele said.

He was charged with first-, second-, and third-degree murder, robbery, receiving stolen property, and related crimes in the death of Carlin-Kraft, whose body was discovered the night of Aug. 22 by Lower Merion police conducting a wellness check in her second-floor unit  at the Cambridge Square apartments at 120 Sibley Ave. According to the warrant filed in his arrest, she met Harris in Center City just hours earlier.

She had been severely beaten and had black eyes and a broken nose, Steele said. The cause of her death was listed as "ligature strangulation," meaning the killer used a cordlike object, such as a rope, to choke her until she died. Steele said he could not comment on what was used to strangle Carlin-Kraft but said investigators were analyzing objects found in her apartment.

"For someone's life to be taken with strangulation takes a lot of pressure and time," Steele said. "This is a violent death, and we will pursue justice."

Court records show Harris was released from the State Correctional Institution at Greene on July 15 after serving a three-year sentence on robbery charges. His arrest record includes drug possession, assault, and harassment. Harris, a native of Johnstown, Cambria County, has a sister who lives in Philadelphia, according to his arrest warrant.

Police in Lower Merion were led to Harris by a tipster who recognized him from surveillance images released Monday by the District Attorney's Office. The tipster, who is known to law enforcement but whose identity was not disclosed in the warrant, said he or she received text messages from Harris just before 3 a.m. on Aug. 22, two hours before police believe Carlin-Kraft was killed.

"I just met this sexy-ass white [expletive]," Harris allegedly texted the tipster, according to the warrant. "I'm at her crib in Ardmore."

With help from the tipster, as well as other sources, investigators determined that Harris had fled the area and was heading toward Pittsburgh.

Investigators were first called to Carlin-Kraft's apartment around 9:15 p.m. on Aug. 22 by Alexander Ciccotelli, her boyfriend. Ciccotelli, who splits his time between New York and Ardmore, had told police he was concerned because he hadn't spoken to her since Aug. 20 and she wasn't answering his calls or texts. He said he had been unable to enter the apartment — which he owns — because the dead bolt had been locked from inside.

When police forced the door, they found Carlin-Kraft dead in a bedroom. She was in bed, with pillows, sheets, and a comforter all around her, and the carpet and walls were "significantly bloodstained," according to the warrant.

Once inside the apartment, Ciccotelli told police he noticed that a white shirt that he kept in the apartment was missing, as was Carlin-Kraft's iPhone and house keys.

Surveillance from the apartment building shows Carlin-Kraft leaving alone just after 1 a.m. on Aug. 22, and returning two hours later with a man investigators believe was Harris.

The apartment's security system showed that someone exited from the "apartment's back door onto a terrace" at 5:19 a.m. and that no one else had entered the unit until police arrived.

Additional surveillance from around Carlin-Kraft's apartment building showed the man believed to be Harris walking beneath the terrace connected to her unit just before 5:30 that morning.

Detectives were able to follow his movements using other surveillance as he walked on Montgomery Avenue and later City Avenue.

Days later, detectives found the shirt that Ciccotelli had reported missing from the apartment about a block away, in shrubbery near Sibley and Church Road. The shirt appeared to be bloodstained.

Detectives also found Carlin-Kraft's iPhone near Montgomery and Bryn Mawr Avenues in Bala Cynwyd.

Detectives from Montgomery County contacted officials from Lyft, whose records showed that Carlin-Kraft had taken a vehicle at 1:11 a.m. into Center City, the warrant states. The ride-share driver who picked her up told police that she was alone and had requested to be dropped off near the corner of Broad and Chestnut Streets, with one stop in Manayunk.

Surveillance collected from Broad and Chestnut showed her walking to Broad and Locust Streets, where she allegedly encountered Harris. The two walked the streets in the area for a short period before appearing to enter a parked vehicle.

Lower Merion detectives late Wednesday were on their way to Pittsburgh to interview Harris, and Steele said it could be some time before he is transported to Montgomery County.

Detectives, meanwhile, are continuing to investigate a burglary reported at her apartment days before her death. Andre Melton, of Southwest Philadelphia, was being sought in that case, according to a warrant filed in Ardmore District Court last week.

Steele said Wednesday that it was unclear whether the burglary is connected to her homicide. It occurred under similar circumstances, with Carlin-Kraft taking a Lyft into Philadelphia on Aug. 17, only to return hours later with Melton, authorities say. In reporting the burglary, she told police her memory of the evening was fragmented, and couldn't remember how she had gotten home.

A man believed to be Melton was seen on surveillance leaving her apartment early the next morning with a box full of what police believe were her belongings, including designer purses and jewelry. Police recovered those items on Aug. 22 inside Melton's home.

Anyone with information on Melton was asked to call Montgomery County detectives at 610-278-3368 or Lower Merion police at 610-649-1000.