BALTIMORE — A Russian man has been named as a suspect in the death of his mother who disappeared while visiting him in Maryland, Baltimore County police said Wednesday.

Dmitry Pronin, 26, is the suspect in the death of Yulia Pogrebenko, 54, of Irkutsk, but he has not been charged, according to police spokeswoman Elise Armacost.

Police are awaiting information from Russia before completing the investigation, she said. The request for documents is being processed, according to a Russian embassy spokesman.

Pronin is serving 10 years in prison for an armed bank robbery in Delaware that happened just days after his mother’s arrival in the U.S., Armacost said.

Police appealed to the public for help finding Pogrebenko in May, saying the university professor was last heard from on Feb. 23 as she drove from Kennedy International Airport in New York to Pronin’s home in Catonsville. Russian officials said Pogrebenko’s sister reported her missing on March 23. After county police were notified of her disappearance on May 12, her rental car was found in the Baltimore area.

In August, police announced that a body found in June by a boater south of the Chesapeake Bay Bridge had been identified as Pogrebenko, but her death was classified as undetermined at the time. Russian officials said they provided DNA samples to help identify the body.

On Wednesday, police announced that her death had been ruled a homicide, but declined to release a cause of death.

Pronin pleaded guilty in September to an armed robbery at a Wilmington-area WSFS bank in March — about 10 days after his mother’s arrival in the U.S. He was expected to be deported after serving the sentence in New York.

Pronin, who came to the U.S. in 2008 on a work visa that was later adjusted to a student visa, told the FBI during the robbery investigation that he had married a woman with significant mental disabilities in an attempt to stay in the country legally, according to the Delaware U.S. Attorney’s Office.