ALEXANDRIA, Va. (AP) — Six members of the MS-13 street gang were convicted Monday for their roles in the slaying of a northern Virginia teenager they believed was a rival gang member.

A jury at a federal court in Alexandria returned guilty verdicts on all counts against the six defendants, who were residents of Alexandria and Leesburg. Four of the six face mandatory life sentences. A fifth faces up to 25 years, and a sixth faces a potential life sentence.

Four others charged in the death of 18-year-old Carlos Otero-Henriquez had already pleaded guilty and received sentences ranging from 15 years to life.

Otero-Henriquez — who had posted pictures of himself on Facebook making gang signs of the 18th Street gang, a rival to MS-13 — was stabbed more than 50 times in May 2016. He was lured out on the pretense of going to a party.

The case is one of several in the region that marked a resurgence of MS-13 in recent years.

"The hallmark of MS-13 is extreme violence," said Tracy Doherty-McCormick, acting U.S. Attorney for the Eastern District of Virginia, which prosecuted the case. "This brutal kidnapping and murder is a tragic reminder of the impact MS-13 has on communities here in Northern Virginia.