The MS-13 gang member filmed the killing with a cellphone, barking out orders and narrating as fellow gang members set upon the 15-year-old girl with a knife and a large wooden stake in a suburban Virginia park, an FBI agent testified Monday.

The green-light to kill Damaris A. Reyes Rivas had come from the transnational gang’s leadership in El Salvador, payback for her alleged role in luring another MS-13 member to his death a week earlier, the FBI agent told a Fairfax County judge.

But it was 17-year-old Jose Cerrato who allegedly helped orchestrate the killing, part of a plan to send the video back to those MS-13 leaders as proof of his willingness to carry out orders, the agent testified. It’s unclear if the video was ever sent, but the FBI agent testified Cerrato soon earned a promotion within the ranks of the gang for his role in the slaying.

The testimony by FBI special agent Fernando Uribe came during a hearing in Fairfax County juvenile court in which a judge certified that Cerrato would face murder, abduction and gang participation charges as an adult.

He is one of 10 people charged in connection with Damaris’s killing on Jan. 8 in the Springfield area.

(Claritza Jimenez/The Washington Post)

The intertwined pair of killings have highlighted the resurgence of MS-13 in the area, resulted in the arrests of 18 teenagers and young people, and underscored the lethality of a gang, which enforces internal discipline in a brutal fashion.

“If someone dies in a clique as a result of a fellow member, the person is killed in retaliation,” FBI Special Agent Fernando Uribe testified in Fairfax County juvenile court.

Uribe relayed the grim events leading to Damaris’s body being dumped facedown next to a set of railroad tracks that run beneath the Beltway not far from Springfield’s Lake Accotink Park. Police discovered her remains under a pile of railroad ties.

Damaris had left her Gaithersburg, Md., home in mid-December and fallen in with MS-13, her mother said. Roughly a week before her slaying, Christian Sosa Rivas, 21, of Fairfax, was lured to his death and killed because he was claiming to be a leader of MS-13 and angered other gang leaders, according to a search warrant. Sosa Rivas’s body was discovered along the Potomac River in Dumfries.

Uribe testified Cerrato was close friends with Sosa Rivas and he and other gang members hoped to get Damaris to admit on video that she played a role in helping lure Sosa Rivas to the location where he was attacked. Eight people have been charged in connection with his killing.

Damaris was lured to Lake Accotink Park, where she was interrogated and beaten by a group of MS-13 members, Uribe testified. At one point, Damaris was made to take off her clothes on the frigid day, so “she could feel the cold that Christian did,” Uribe testified.

Uribe previously testified at a preliminary hearing for another co-defendant that Damaris had admitted under questioning she had a sexual relationship with Sosa Rivas. In all, three videos of her interrogation were made before she was killed.

On one, Cerrato can be heard urging fellow gang members to walk Damaris into the woods at another location, Uribe testified.

Eventually, 17-year-old Venus Romero Iraheta, who also had a relationship with Sosa Rivas, told Damaris she would see her in hell and plunged a knife into her at least 13 times, Uribe has previously testified. Another gang member then jabbed Damaris in the neck with the wooden stake.

In the end, a search warrant states, the videos shot by Cerrato show Damaris bleeding among dead leaves.