Federal prosecutors filed a new motion in U.S. District Court on Monday that seeks to extend for six more months the forced medication of alleged Capitol Police shooter Russell Weston Jr., prompted by what one forensic psychiatrist described as a “dramatic” change in Weston’s behavior in recent weeks.

Weston, a diagnosed paranoid schizophrenic, is charged in the July 1998 shootings that killed Capitol Police Officer Jacob Chestnut and Detective John Gibson.

Weston has been forced to take anti-psychotic medication since January 2002, in an attempt by prosecutors to make him fit to stand trial. But the landmark — and to some civil libertarians controversial — court order that green-lighted Weston’s medication is set to expire May 19.

During a Wednesday hearing before federal Judge Emmet Sullivan, Special Assistant U.S. Attorney Ronald Walutes said the motion came in response to behavioral changes observed by staff at the Federal Correction Institute in Butner, N.C., where Weston is housed.

According to forensic psychiatrist Sally Johnson, who works at the North Carolina facility, Weston made his second “biggest step” toward competency when he took part in a mid-April mock trial exercise, held as part of group therapy class.

The class, moderated by a social worker, is intended to teach patients at the facility about various aspects of the legal process, including the role of the judge, the attorneys and the jury. Such exercises periodically include a mock trial, Johnson told the court.

During the April 22 class, which Johnson did not attend, Weston played the role of the defense attorney in a federal counterfeit case.

According to Johnson, Weston performed in the “upper echelon” of patients participating in a mock trial. She testified that the class facilitator told her: “If I was going to trial, I would hire Mr. Weston as my attorney.”

Johnson noted that prior to the mock trial, she had considered Weston “non-restorable.” However, his performance “floored me,” she said.

Noting other developments in Weston’s behavior — including strides toward becoming “more functional” and “more verbal” — Johnson said that Weston could achieve the mental competency required to stand trial. She recommended the six-month extension of medication sought by prosecutors.

“There is still a significant likelihood his competence will be restored,” Johnson testified. Weston, who has been given various drugs during the past two-plus years, is currently taking Clozaril, which Johnson has repeatedly described as the “gold standard” of anti-psychotic medications.

Federal public defender A.J. Kramer said Wednesday that he will file a motion seeking to deny the extension and promised to include arguments similar to those he made in opposition to an earlier six-month extension.

In that motion, filed in February, Kramer argued that Weston’s mental state had not significantly improved since he began medication in 2002.

Kramer noted Weston’s numerous delusions, including assertions that he is a law enforcement official and that staff at Butner are escaped federal prisoners. Weston also has claimed to be a graduate of Harvard University, holding advanced degrees from both its law and medical schools.

If Weston is not found competent to stand trial — a standard that requires a defendant to understand the proceedings and to be able to adequately assist in his own defense — he could eventually be committed involuntarily and on a long-term basis to a secure hospital facility rather than a prison.

In such a situation, Weston, who has been indicted but never tried, would not be found to bear criminal responsibility for his alleged actions.