Armed with two machetes and a sawed-off shotgun, MS-13 gang members allegedly set off in a car last October to carry out an assassination at a location as brazen as it was chilling: a Prince William County school.

The plan was to shoot a wayward associate nicknamed “Peligroso,” or danger, as he left Gar-Field High School in Woodbridge after night classes wrapped up, according to a search warrant.

But the carload of armed gang members was stopped by authorities as they rolled into the school’s parking lot, court records show. An informant had tipped off police just a day earlier.

The narrowly averted hit was part of a nine-count indictment against members of MS-13 unsealed Friday in federal court in Alexandria. Thirteen purported gang members have been charged in connection with the attempted murder and with three killings across Northern Virginia and are in custody. Eleven of the defendants could face the death penalty or life in prison if convicted.

Gang experts said the case is part of a resurgence of the region’s largest and most dangerous gang after crackdowns by law enforcement in recent years decimated its leadership and members. Also known as Mara Salvatrucha, the gang once had a strong and visible foothold in the D.C. region, with members linked to brutal machete attacks, killings and other violent crime.

“We’ve seen a reemergence or reconstitution of MS-13 over the last year and a half. With that has come an increase in violence,” said Michael McGarrity, assistant special agent in charge of the FBI’s Washington Field Office. “They are being more organized in what they do, how they do it and what they do it for.”

Experts traced the renewed activity to the gang’s leadership in El Salvador trying to create a more disciplined and structured organization in order to rejuvenate its ability to make money. Most of the recent violence has targeted MS-13’s own members or those of rival gangs, not the general public.

This year, federal prosecutors have announced indictments tying MS-13 members to at least eight slayings in the Maryland and Virginia suburbs that took place in recent years, as well as extortion, rape and assault.

The charges unsealed Friday in U.S. District Court allege that members carried out the three killings in Fairfax County and Alexandria and the attempted murder in Woodbridge as an initiation rite or to further their position in the gang. All of those charged are in custody.

In the Alexandria killing, a dispute started between gang members and 27-year-old Julio Caesar Urrutia-Erazo, an Alexandria man, in the 3800 block of Russell Road on June 19, according to court records.

Someone took a swing at Urrutia-Erazo when he said he was not in a gang, witnesses told police. Then a gang member named Jesus Alejandro Chavez, who goes by the nickname “Taliban,” shot Urrutia-Erazo, authorities said in court records. The man died two days later.

Chavez and two other gang members have been charged with murder in aid of racketeering. Jerome P. Aquino, one of Chavez’s attorneys, declined to comment, saying he was only recently appointed to the case.

The indictment provides few details about the two Fairfax killings. Three MS-13 members were charged with murder in aid of racketeering in the killing of Nelson Omar Quintanilla Trujillo on Oct. 7, 2013, shortly after the attempted hit at Gar-Field. The defendants allegedly buried his body with the help of another gang member. The victim’s age and home town were not released.

And on March 29, seven MS-13 members were charged with murder in aid of racketeering in connection with the death of a man named Gerson Adoni Martinez Aguilar. No other details about him were given.

Authorities became involved in the Gar-Field High School case on Sept. 30, 2013, according to a search warrant filed in Fairfax County court. The confidential informant contacted Prince William police, who shared the information with the FBI.

The gang members held a gathering in Falls Church the same day the tipster alerted authorities, court papers say. At the meeting, the informant told police, high-ranking members of the gang devised a plan to carry out the killing.

They wanted the target dead, the informant said, because he was not following the gang’s rules.

On the evening of Oct. 1, the FBI along with Fairfax and Prince William police devised their own operation to counter the plot, according to the search warrant: They stationed the Prince William police cruiser in the parking lot of the school to intercept the gang members.

“It’s very disturbing, because I thought we as a county had this under control,” said Carlos Castro, a member of Gar-Field’s parent-teacher organization.

The U.S. Attorney’s Office for the Eastern District of Virginia, which is handling the case, declined to comment. Attorneys for other defendants also declined to comment or could not be reached.

The charges in Virginia follow federal indictments against 12 MS-13 gang members in Prince George’s County earlier this year on charges ranging from murder to rape, to kidnapping and extortion.

Federal prosecutors in Maryland alleged that over a period of five years, members of several cliques killed rivals in other gangs, extorted brothels and high school students, and attempted to kill witnesses slated to testify against gang members.

MS-13 originated in Los Angeles in the 1980s, founded by men who had fled El Salvador’s civil war. It spread eastward and gained the attention of law enforcement in the region in the 1990s.

The gang began to grab headlines about a decade ago with a series of gruesome attacks. In one, gang members used a machete to slice a teen’s fingers off; in another, MS-13 killed a pregnant member who was cooperating with federal authorities.

The tactics prompted police to crack down on the gang, which has 1,000 to 3,000 members across the D.C. area. In 2011, law enforcement said the gang had pulled back from such violence to focus on criminal enterprises, like sex trafficking.

Local and federal authorities have targeted those operations in a series of high-profile prosecutions.

McGarrity, the FBI’s assistant special agent, said the close coordination of federal authorities and Northern Virginia’s police departments made the successes against MS-13 possible. He said there have been fewer incidents of violence in the last few weeks, one good sign.

Still, the gang seems to have entered a new phase.

“MS-13’s activity was more hidden for a number of years,” said Douglas Keen, chairman of the Northern Virginia Regional Gang Task Force and the police chief of Manassas City. “Now they are coming back out and being more brazen.”

Peter Hermann and Julie Zauzmer contributed to this report.