A member of Northern Virginia's most violent street gang, Mara Salvatrucha, was charged yesterday in the fatal shooting of a 22-year-old Manassas Park man, police said.

Wilfredo Montoya-Baires, 25, a construction worker from Reston, was found at an apartment complex in the Seven Corners area by gang investigators from Fairfax and Prince William counties. Police said he agreed to be interviewed at the police station in Manassas, where he subsequently was arrested.

Montoya-Baires, whose nickname is "Nino," was charged with first-degree murder in the slaying of Jose N. Escobar, who was shot Wednesday night, they said.

Escobar's slaying is the 10th Hispanic gang-related homicide in Northern Virginia since 2000. Police said Mara Salvatrucha, or MS, is the dominant street gang, with about 2,500 members in the region, and that gang violence has been escalating in recent years.

Montoya-Baires, who sports an MS marking on his stomach, also was charged with using a firearm while committing a murder and will have a hearing Sept. 21, according to court records. He is being held without bond at the Prince William jail.

The father of the victim, Daniel Escobar, said yesterday that his son and Montoya-Baires were friends.

"I know him. I saw him a couple times with Jose," Daniel Escobar said. "Sometimes they would go to a discotheque or a 7-Eleven. This is surprising. I feel better that he's in jail."

Police said additional charges against Montoya-Baires are pending and that more arrests could be made in the slaying. Sgt. Richard Cantarella of the Prince William County Police Department said that "the investigation is not over by any means" and that authorities still are searching for others who "took an active role in the killing."

Escobar, who worked for a Loudoun County construction company, was shot in the chest during a party and found by police lying in the hallway of a two-story townhouse in the 8100 block of Community Drive in Manassas.

Marcus Smith, who lives across the street, said the victim's uncle rushed to his house to call 911 about 9:30 p.m. after the shooting. The uncle told Smith that he had come to the party only because "somebody from that house called his cell phone to say there was an argument and a fight was going down," Smith said.

Smith said the uncle was "pretty shaken up" and "all he kept saying was, 'That's my family's house.' "

Another neighbor, Helmi Banegas, said the owner of the house had called police before to report suspicious activity at the house.

"You always see [young] people moving in and out with fancy cars at the house," said Banegas, "like Mercedes, Jaguars, BMWs."

Banegas said he watched police perform CPR on Escobar before he was flown to Inova Fairfax Hospital, where he died during surgery.

One law enforcement source, who agreed to speak on the condition of anonymity, said the slaying "escalated out of the fight." He said that extra sheriff's deputies and Prince William County police will be on hand for Escobar's funeral next week, which "will probably be attended by a lot of people who may have a proclivity to show their [gang] colors."

According to court records, Montoya-Baires was born in El Salvador, where MS has its roots. His appointed attorney, Barry Zweig, declined to comment, saying only, "He's going to get an aggressive defense."

Staff writers Tom Jackman and Maria Glod contributed to this report.