The man accused of killing his much older socialite wife in their Georgetown home had tried to get a drug dealer to "do away with her," according to prosecutors.

Albrecht Muth, 48, is charged with first-degree murder in the August 2011 beating and strangulation death of 91-year-old Viola Drath. Prosecutors are seeking to admit Muth's conversation with the drug dealer and other alleged threats and acts of violence against Drath as evidence in the defendant's upcoming trial.

The incident with the drug dealer occurred months before Drath was killed. Muth allegedly told the dealer that he wanted to get control of the money of the "old lady." Although Muth had described this woman as his stepmother, prosecutors wrote in a motion that he was referring to Drath.

Additionally, Muth has a history of physically abusing Drath. He was convicted of assaulting his wife in 1992. He was also arrested for a 2006 assault, but he was never convicted in that case because Drath asserted marital privilege. On other occasions, witnesses saw Muth assault Drath or were told by the socialite that Muth had been violent toward her.

A few days before her death, Drath told a friend that Muth had threatened her and her grandson. She told the friend that she wanted a divorce and that Muth had complained that he was not receiving a large enough allowance from her, according to the court document.

State Department investigators had been looking into Muth, who took documents that had been disclosed as part of the WikiLeaks scandal and faxed them to the department as if he had inside information. In September 2010, Drath asked to meet with State Department agents and told them that "Muth will do something terrible sooner or later," the document stated.

Prosecutors are seeking to mention past incidents in Muth's trial to show evidence of his motive and to prove his identity as the killer.

Muth's trial is scheduled to begin March 25. He has claimed that he was an Iraqi general and that his wife's death was the result of an Iranian hit job.