Montgomery County Maryland Police have charged two teens Monday in the murder of gay District of Columbia. middle school principal Brian Betts.

Betts, 42, a principal at Shaw Middle School the District of Columbia and a lead figure in education reform efforts in the District, was found dead in his Silver Spring home April 15 by colleagues worried after he failed to show up for work.

According to the Washington Post, Sharif Tau Lancaster and Alante Saunders, both 18, were charged with murder, robbery and a handgun violation. Police said that a third 18-year-old man was being held and that they expected that he would also be charged in the killing.

Investigators say they think the trio used a phone hook-up line line to find a target to rob and Montgomery Police Chief J. Thomas Manger said today that there was no indication that Betts alleged killers had any relationship with Betts before he arranged a meeting with one or more of them on the phone line.

District of Columbia officials also say that Lancaster and Saunders had recently escaped from the custody of a D.C. Department of Youth Rehabilitation Services home, but it was not clear whether they were considered escapees at the time of Betts’s killing.

According to Chief Manger, investigators tracked the trio down after Lancaster, Saunders and Lancaster’s mother used credit cards stolen from Betts at several DC area businesses and from fingerprints police found in Betts home and in his stolen SUV.