An FBI agent testified Monday that an MS-13 gang member filmed and narrated the killing of a 15-year-old girl in a Virginia park, according to the Washington Post Monday.

Damaris Reyes Rivas, 15, was killed in a Fairfax County Virginia park on Jan. 8, 2017. Authorities said Venus Romero Iraheta, 17, was one of ten members of the MS-13 gang who killed Rivas. The gang members were reportedly authorized to kill Rivas because they claimed she had a role in the death of her boyfriend, a fellow MS-13 gang member named Christian Sosa Rivas. The two were of no relation. Eight others are tied to the death of Sosa Rivas in early January 2017.

Read: How The MS-13 Street Gang Was Started In The US

Iraheta allegedly told Rivas, “see you in hell” before stabbing her 13 times with a knife. Another gang member then used a wooden stake to stab her in the neck. Iraheta previously had a sexual relationship with Sosa Rivas.

A 17-year-old boy named Jose Cerrato reportedly helped plan Rivas’s killing. He filmed Iraheta stabbing her because he planned to send the video to MS-13 leaders as proof that he could follow orders.

It is unclear if the video was sent, but Cerrato was promoted within the gang after the killing, testified FBI Special Agent Fernando Uribe to a Fairfax County judge Monday.

A Fairfax County judge ruled Iraheta would be tried as an adult, according to CBS-affiliate WUSA in May 2017. Cerrato, as well as four other gang members, would also be tried as adults. Iraherta and Cerrato face murder and other charges.

MS-13, short for Mara Salvatrucha, was established in the 1980s as an international criminal gang meant to protect Salvadoran immigrants in California from other gangs. The gang presence grew and it is now active in 42 states, Washington D.C. and parts of Central America, mostly El Salvador. The 13 in the name indicates the 13 seconds members are beaten as part of gang initiation. The FBI reported that MS-13 has over 6,000 members. 

“If someone dies in a clique as a result of a fellow member, the person is killed in retaliation,” Agent Uribe said Monday.

Read: How Many MS-13 Gang Members Are There In US? Los Angeles Police Arrest 21 Members

Cerrato was close friends with slain 21-year-old  Sosa Rivas. He and other members of MS-13 lured Rivas into a park on Jan. 8, where they interrogated her over her involvement in the death of Sosa Rivas. Iraheta also reportedly cut off Rivas’s diamond tattoo. 

Agent Uribe testified that the gang members tortured Rivas and forced her to strip so she could feel the pain Sosa Rivas felt before he died. According to the search warrant, video footage shot by Cerrato show Rivas bleeding on the ground.

more mugshot 2 Jose Castillo Rivas and Wilmer Sanchez-Serano are two of the ten charged with the murder of Damaris Reyes Rivas. They were charged as adults. Photo: Fairfax Police Department more mugshot Cindy Blanco Hernandez and Aldair Miranda Carcamo are two of the ten charged with the murder of Damaris Reyes Rivas. They were charged as adults. Photo: Fairfax Police Department