The Justice Department plans to pursue the death penalty for a member of the MS-13 gang accused in the kidnappings and killings of two Virginia teenagers in 2016, a move that comes as the Trump administration fights to restart federal executions.

Elmer Martinez is alleged to be the leader of the Fairfax County clique that authorities say killed a 17-year-old suspected of belonging to a rival gang and a 14-year-old who revealed that crime to the victim's family.

In a court filing Monday, prosecutors said Martinez was singled out for death among the dozen-plus people charged in connection with the crimes because of his “substantial planning and premeditation” and “his lack of remorse for his violent acts”.

The Trump administration announced plans in July to resume executing federal prisoners, after a 16-year moratorium. A judge blocked the executions in November, determining that the Justice Department's proposed lethal-injection procedure “is not authorised” by federal law.

The Supreme Court refused to let executions resume while the legal battle continues.

Tattoos of the Mara Salvatrucha Show all 9 1 /9 Tattoos of the Mara Salvatrucha Tattoos of the Mara Salvatrucha An ex-member of the MS-13 gang is pictured at Santa Ana prison, 60km northwest of San Salvador. Former members of Salvadoran gangs are willing to endure a painful process with laser technology to erase tattoos they now say were a "youth mistake" AFP/Getty Images Tattoos of the Mara Salvatrucha Inmates, members of MS-13 and Barrio 18 gangs, wait upon arrival at the maximum security prison in Zacatecoluca, 65 kilometres east of San Salvador. Forty-eight members of violent gangs were arrested in 2017 in connection with the murders of policemen and soldiers AFP/Getty Images Tattoos of the Mara Salvatrucha A member of the MS-13 gang remains in Chalatenango prison. Central American countries have a prison population of 134,800 inmates. Despite the construction of new infrastructure they are kept cramped in jails, in some cases exceeding African average detention rates AFP/Getty Images Tattoos of the Mara Salvatrucha An ex member of the MS-13 gang at Santa Ana prison AFP/Getty Images Tattoos of the Mara Salvatrucha A member of a violent gang waits at the maximum security prison in Zacatecoluca AFP/Getty Images Tattoos of the Mara Salvatrucha Former MS-13 gang leader Valmis Mejia, aka 'el Bambi', at Santa Ana prison AFP/Getty Images Tattoos of the Mara Salvatrucha An ex member of the MS-13 will spend years getting rid of the tattoos AFP/Getty Images Tattoos of the Mara Salvatrucha Former MS-13 gang leader Valmis Mejia AFP/Getty Images Tattoos of the Mara Salvatrucha View of the tattoos of an alleged member of the 18 gang as he is presented to the press in San Salvador on February 26, 2016. Members of the national civil police and the armed forces captured 240 dangerous gang members accused of homicide and extortion in the last three days in different areas of El Salvador. The country faces an escalation of violence attributed mostly to the war between the MS-13 and 18 ST gangs AFP/Getty Images

President Donald Trump makes frequent references to MS-13 by its full name, La Mara Salvatrucha, including in his most recent State of the Union address, in which he said a border wall was needed to keep the “savage gang” out.

The gang formed in Los Angeles during the 1980s by El Salvadorans and has taken over large swaths of Central America and regions in the United States, including pockets of the Washington area.

Defence attorney Robert Jenkins said he was informed by the Justice Department of its decision, a step he said he believed was taken to support the president's stance on illegal immigration.

“I strongly suspect politics is playing a significant role rather than whether or not this is the appropriate thing to do to serve justice,” Mr Jenkins said. “Whether or not they truly believe that justice would be served by seeking the death penalty I think is maybe a secondary concern versus what political chips they can gain with his base by appearing to be tough on illegal immigrants.”

Jenkins said Martinez, an immigrant from El Salvador, did not have a violent criminal history and is not alleged to have inflicted blows in either slaying.

In their filing, prosecutors said Martinez has a history of uncharged violent conduct, including assaults, stabbings and another attempt at kidnapping and homicide. While in jail awaiting trial, they say he was twice found with a shank.

Police remove crime scene tape on where two bodies were found in Holmes Run Park (The Washington Post)

The deaths of Edvin Mendez and Sergio Triminio came during a grisly spike in violence in the Washington region that has since abated amid a crackdown by law enforcement. Killings connected to the gang in the area fell from at least 33 in 2016 and 2017 to seven the following year.

It was in the summer of 2016, according to court documents, that a member of the Park View Locos Salvatrucha group saw the photos on Mendez's Facebook page that would lead to his death: a man surrounded by three 6s. The image led them to mark Mendez, an aspiring member, as a spy for the rival 18th Street Gang. Authorities said local MS-13 leaders agreed Mendez should be killed, sending members from Maryland to Virginia to help.

They lured Mendez to Holmes Run Stream Valley Park under the pretence of a gang meeting, according to an indictment, where they killed him and buried his body. They took turns filming the murder, authorities allege, a video that was sent to gang leaders to help the killers earn promotions.

Fairfax County, Virginia, Police Chief Edwin Roessler Jr talks to the media (The Washington Post)

Mendez's family spent the weeks after his disappearance searching anxiously for information. His brother reached out on Facebook to Triminio, an acquaintance. An associate of MS-13, Triminio admitted that Mendez had been targeted for death by the gang, authorities said.

A day later, according to court records, Triminio got a message on Facebook telling him to go to Fairfax for a gang meeting. His family last saw him leave their Alexandria, Virginia, apartment in his pyjamas to take out the trash. His body was found near Mendez's in another shallow grave.

That killing was also recorded. A video recovered from one participant's phone showed a young man in pyjamas being attacked with a kitchen knife and machete as he lay face down on the ground, according to a federal indictment.

Prosecutors say the gang had come to believe Triminio also spoke to the police.

Beyond Martinez, 10 more gang members will go to trial in connection with the killings but are not facing the death penalty. Two more were not charged with murder, although court records indicate they were involved. They could be called to testify at trial.

Jay Lanham, the executive director of the Northern Virginia Regional Gang Task Force, said the Holmes Run killings represented a peak in the gang's activity in recent years.

“That was high tide of homicides,” Mr Lanham said. “Since then, homicides have subsided somewhat. We are still seeing MS-13 members keep a low profile. We saw them lose a lot of leadership.”