Even an alleged drug dealer on trial in federal court cannot resist promoting himself on Twitter or Facebook.

In tweets and Facebook postings from a smartphone apparently smuggled into the D.C. jail, the accused drug kingpin has regularly updated friends and followers about his life and times, opining about his “beef” with the government and engaging in 140-character conversations filled with slang and expletives about life on the street and behind bars.

But authorities, who have been monitoring his online musings for weeks, say they are concerned that Mark Pray might have more nefarious motives in mind — like trying to influence his high-stakes trial in the District’s federal court. Last month, court papers show, Pray posted an update on his Facebook page and in his Twitter feed about the upcoming testimony of a witness, nicknamed “Hag,” whom Pray contended was going to “sell his soul” on the witness stand.

Federal authorities said in court papers that the comments — available for the world to see — were intended to urge associates to attend the trial and “to intimidate” the witness. When the man finally testified, Pray took to Facebook again, telling his friends that the witness “looked like Chucky Cheese on the stand today! (A Big Rat).”

“I can’t stand ratsssssssss,” a friend replied.

Pray’s use of social media was disclosed in an affidavit by U.S. Park Police Detective William Sepeck this week seeking permission from a federal judge to search Pray’s jail cell for contraband, including mobile phones.

The D.C. jail bans such devices and regularly conducts sweeps for them, officials said. Though no mobile devices were found in the search on Tuesday, authorities recovered what they described as an incriminating note from a co-defendant that prosecutors would like permission to introduce at trial. Last week, prosecutors presented at least one of Pray’s Facebook posts — about the witness — to jurors.

A. Eduardo Balarezo, one of Pray’s attorneys, declined to comment about his client’s online habits, citing the ongoing trial. In court papers, Balarezo and his co-counsel, Jenifer Wicks, unsuccessfully sought to block prosecutors from presenting Pray’s social media updates to jurors.

Pray, 31, his alleged “enforcer,” Alonzo Marlow, 30, and a third man, Kenneth Benbow, 31, are on trial on charges of conspiring to run a powerful drug gang in the Barry Farm public housing project in Southeast Washington from at least 2006 through early 2010. Prosecutors have called the gang extremely violent and have linked Pray to three killings, including the 2009 execution-style slaying of a government witness.

Their trial started Feb. 1 and is expected to conclude in coming days.

It is not surprising that Pray would continue to use social media, even from behind bars.

Last year, federal agents obtained a warrant for information related to Pray’s Facebook page. At the time, Pray was using the alias, “Kiaser Sorsay,” on the site and even discussed his illicit business in comment threads, federal agents alleged in the warrant.

In the days before his arrest, agents wrote, Pray posted on Facebook that “I told fb this mornign that the streets don’t love me. Jumpers came like I had a bomb strapped to me.” Federal agents translated the comments to mean that Pray was concerned about “ ‘jump out’ police officers — generally vice officers — who patrol the Barry Farm neighborhood.”

Agents added that one of Pray’s associates was updating his Facebook page “via Mobile Web,” despite being incarcerated at the D.C. jail.

In recent months, authorities say, Pray has used another alias on Facebook, where his profile photograph shows him holding a young child. Like anyone else on the site, he regularly updated the world about his thoughts, joys and woes. “Happy Valentines day 2 all of my fb fam and friends,” he wrote last month. On another occasion, he offered this advice: “When face to face with adversity, MAN up.”

On Twitter, he used the name Iceberg Slick and the handle @playyboye and once had a profile picture of him on a wanted poster, court papers say.

According to data from Twitter, he tweeted using smartphones and often opined on rap lyrics while expressing himself in expletives and street slang. “Man i gotta get my soul right,” he tweeted at noon one Saturday in March, reciting lyrics from the hip-hop artist Lucifer.

The next day, he tweeted, “Before I get [where] I’m going I just gotta be fresh!!! Top of the morning.”

At 12:50 a.m. Tuesday, just hours before authorities raided his cell, Pray tweeted a photo of a stack of $100 bills and wrote, “My name LUVA, and im addicted to money.”

Since the raid on Tuesday, his Twitter and Facebook accounts have been silent.

Staff writers Greg Linch and Katie Rogers contributed to this report.