A 33-year-old Sterling man was the subject of a police manhunt yesterday after being charged with strangling his girlfriend Monday morning in the Fairfax County office building where they both worked.

Police said co-workers of Robin J. Kehrer, 24, found her body about 10:30 a.m. in the building at 3975 Fair Ridge Dr. in the county's Fair Oaks section, where she and her boyfriend worked for Inacom Government Systems. Her body was hanging from the stairwell, with a belt wrapped around her neck and attached to the banister, according to a police affidavit. An autopsy yesterday determined that she died by asphyxiation.

About an hour before the discovery of her body, two co-workers had seen Kehrer talking with her boyfriend, Jason A. Morant, outside the stairwell, the police affidavit said. Police said one witness told them that he later heard "a rumbling and a scream."

Several Inacom employees then searched the area, and Morant was gone from the building by the time Kehrer's body was found, police said.

Detectives obtained a murder warrant for Morant on Monday evening.

Morant and Kehrer lived together in a town house in the 21000 block of Goldstone Terrace in the Rolling Woods subdivision of Sterling, according to the affidavit, which was filed in Loudoun County Circuit Court by Fairfax Detective Steve Shillingford. Police said they believe the killing was related to a domestic dispute.

Neighbors said the couple moved in this year and kept mostly to themselves.

Kehrer's two small children lived in the house, according to police and neighbors, and police said they believe Morant was the father of one of the children. Police said they did not know the ages of the children, who were in the care of relatives last night.

On Monday night, police searched both the Sterling town house and Morant's cubicle at Inacom. According to the search warrant, Loudoun sheriff's deputies had been dispatched to the town house last Wednesday in response to an attempted suicide by Morant. Loudoun and Fairfax authorities declined to provide further information about the incident.

The search warrant also said police were looking for belts possibly worn by Morant that could be compared to the belt found at the crime scene. Detectives removed items from both the town house and Morant's work space, but police did not provide details on what was taken.

Inacom Government Systems is a subsidiary of Inacom Corp., a Fortune 500 company with more than 11,000 employees worldwide, and designs computer systems for corporations and government agencies, according to Geri Michelic, an Inacom spokeswoman at the company's headquarters in Omaha. About 100 people work in Inacom's Fair Oaks office.

Morant is a sales representative for the company, and Kehrer was an account manager, said Mark O'Donnell, an Inacom vice president. Kehrer was hired in January and was "an extremely well-liked employee," O'Donnell said. "She had a smile that would light up the room. She was a very good employee." Company officials declined to talk about Morant.

Inacom released a statement yesterday that said the company was "deeply saddened by this tragedy and the loss of Robin Kehrer." A crisis intervention team visited the company's offices to help workers handle the situation.

Morant is described by police as 6 feet 1 inch tall, weighing 240 pounds, with brown hair and brown eyes. Police said he drives a light blue 1994 two-door Honda with Virginia license plates ZHG-9907.

Staff writer Maria Glod contributed to this report.