Kim Vuong, alongside family members, fourth from left, leaves a news conference in the District on March 25. Vuong’s husband, David Messerschmitt, was found slain at the Donovan Hotel in February. (Nikki Kahn/The Washington Post)

D.C. police on Wednesday arrested a second person in connection with the stabbing death of a 30-year-old lawyer who was found dead in a downtown Washington hotel room nearly two months ago.

Dominique Johnson, 19, was arrested about 7:45 a.m., and she was charged in an arrest warrant with conspiracy to commit armed robbery, according to a statement from D.C. police.

David Messerschmitt was found dead Feb. 10 in a fourth-floor room at the Donovan Hotel on Thomas Circle. He had been stabbed repeatedly in the abdomen, groin and heart, according to police.

Last week police arrested Jamyra Gallmon, 21, and charged her with first-degree murder. The authorities said in an arrest affidavit that she allegedly answered an ad Messerschmitt had placed on Craigslist for a sexual encounter with a man.

She told detectives that she wanted to rob the lawyer, according to the affidavit, but that he grabbed her arm, causing a flashback to a time when she had been assaulted. She acknowledged that she pulled a knife from her sweatpants, stabbed Messerschmitt and took his cash and Metro card, according to court papers. Her attorney asserted in court that it was a case of “imperfect self-defense.”

David Messerschmitt was an intellectual-property lawyer with DLA Piper. (Courtesy of D.C. police)

Gallmon and Johnson were roommates in Southeast Washington, according to court documents related to a rent dispute. About two weeks after Messerschmitt was killed, the two were ordered by a D.C. Superior Court judge to pay $1,860 in rent owed since January. Johnson is expected to make an initial appearance in D.C. Superior Court on Thursday; Gallmon is due in court on Friday.

In court documents, including an arrest affidavit and a search warrant, police described a robbery scheme. Documents said Messerschmitt, an intellectual-property lawyer with DLA Piper, had posted an ad on social media “soliciting responses from other men.” Authorities said they found correspondence between the lawyer and an account linked to Gallmon through her cellphone number and an e-mail address.

Police say Gallmon used the e-mail address chrissanchez0906@yahoo.com and they have urged anyone familiar with the address to come forward to determine if there are more victims. Authorities have not said whether anyone has filed additional complaints.

Police said they found e-mail exchanges from the afternoon of Feb. 9 and that the two arranged to meet in Room 400 between 7 p.m. and 7:30 p.m. Police have said Messerschmitt texted his wife about 7:30 p.m. and said he would return to their Capitol Hill home in about an hour. He was found dead Feb. 10.

Police said in court papers that they found zip ties on Messerschmitt’s fingers that seemed to have been made into handcuffs. A search warrant said police found lubricant and condoms in the room, along with other items. Police said they found a knife in Gallmon’s apartment.

Messerschmitt grew up in a suburb of Cincinnati and attended Boston University School of Law and Ohio State University, where he met his wife, Kim Vuong. He started working last year for DLA ­Piper, an international law firm with its Washington office at Gallery Place.

Vuong has declined interview requests, but she made a public plea for help shortly before Gallmon was arrested. She issued a statement after the arrest — praising police — and added, “I have faith that the police and the courts will bring justice to David and all who loved him.”

A friend of Gallmon since high school has told The Washington Post that she resembled a “person of interest” that D.C. police said had been captured on video surveillance pacing the hotel lobby the day of the killing. But the friend, Brandi Gordon, said Gallmon denied it. Police have not said whether Gallmon is the person on the video.

Gallmon attended Forestville Military Academy in Prince George’s County and played high school basketball. She also worked for MVP Protective Services, a security guard company, for two months before she left in December 2014. The head of the company said Gallmon had wanted to become a police ­officer.

Keith L. Alexander, Eddy Palanzo and Clarence Williams contributed to this report.