A Barry Farm drug dealer who ordered a government witness killed on the eve of his trial and had his Twitter and Facebook accounts updated while jailed was convicted Tuesday of three murders, racketeering and assorted guns and drug charges.

A jury in the District’s federal court returned convictions for murder and the other offenses against Mark Pray, 31, of the District and two of his partners: Alonzo Marlow, 31, also of the District, who worked as Pray’s “enforcer,” and Kenneth Benbow, 31, of Capitol Heights.

The three face sentencing in June for their roles in a vibrant open-air drug market in Southeast Washington and for the violence they used to settle turf disputes and retaliate for snubs as their operation reached into other parts of the District and the surrounding area.

Their attorneys had questioned the reliability of witnesses, particularly former gang members. All three face life sentences.

Pray led an organization that since 2006 distributed PCP, crack cocaine and marijuana in large quantities, an enterprise prosecutors laid out during a trial that lasted more than two months and had the jury deliberating for more than a week. He was convicted of roles in three killings, including ordering the 2009 death of the planned trial witness.

Marlow was convicted of killing that witness and of another fatal shooting in 2010 of Jheryl Hodge, 20 — both at Pray’s behest, prosecutors said.

Benbow and Pray ambushed Van Johnson Jr., a 28-year-old Prince George’s County man, in 2008. He bad-mouthed Benbow before he was killed in a drive-by shooting, authorities said.

The killing of the witness — 44-year-old Crystal Washington of Barry Farm, who was shot six times at point-blank range as she checked out of a halfway house — sparked an FBI investigation and a raft of charges. Several other people pleaded guilty to charges that stemmed from the investigation.

While jailed in the case, Pray’s social media accounts boldly continued to spotlight an upcoming witness and label the man a “big rat” after he delivered his testimony — labels that appeared on Twitter and Facebook and were revealed in a police affidavit. Prosecutors showed one of the posts about the witness to jurors.

The D.C. jail bans inmates from having mobile devices and a search of Pray’s cell after the postings surfaced found no contraband. His accounts went silent after the March cell raid.