The Army has issued a formal reprimand for misconduct to its former top sex-crimes prosecutor after investigating a complaint that he kissed and groped a female officer while attending a conference on sexual-assault prevention, according to Army officials.

Lt. Col. Joseph “Jay” Morse received the reprimand in late June, officials said, four months after the Army received the complaint and suspended him from his job as supervisor of the Army’s special-victim prosecutors.

The Army had not disclosed the outcome of the investigation until Thursday, when it confirmed the result in response to queries from The Washington Post. Lt. Col. Alayne P. Conway, an Army spokeswoman at the Pentagon, said in a statement that Morse was subjected to “appropriate disciplinary action” but did not provide details.

The female captain filed a complaint against Morse in February, nearly three years after she alleged that he groped and kissed her in a hotel room in Alexandria, Va., where both officers were attending a legal conference on sex crimes.

The Army conducted an investigation, but officials in charge of the case concluded that they lacked evidence to file criminal charges.

Army officials said Morse has served notice that he plans to retire. Until then, he has been temporarily assigned to duty at the Pentagon, where he serves in the office of the Army’s judge advocate general. Morse did not respond to e-mails or a request for comment placed through the Army’s public affairs office.

Morse acknowledged an intimate encounter with the woman but said he did not touch her without her consent, according to a sworn statement he gave to investigators.

One of his defense attorneys, Lt. Col. Warren L. Wells, said that Morse “denies and has consistently denied any non-consensual conduct.” He said that Morse passed a polygraph test and that the results were shared with investigators.

The case made headlines in March shortly after the Army began its investigation. The military has been grappling with a spike in reports of sexual assaults in the ranks and a number of embarrassing incidents that have cast doubt on its ability to address the problem.

Last year, the head of the Air Force’s sexual-assault prevention branch was arrested on charges that he grabbed a woman’s buttocks outside a Northern Virginia bar. He was later acquitted. Since then, the armed forces have reassigned several hundred recruiters and sexual-assault counselors after finding that they were unqualified for their positions.

Advocacy groups and many members of Congress are pushing for an overhaul of the military justice system, something that the Joint Chiefs of Staff have vigorously resisted. President Obama has said he will give the Pentagon until the end of the year to demonstrate progress in its handling of sexual-assault cases and then might support such changes.

Army officials declined to elaborate on the specific type of misconduct for which Morse was reprimanded. Under military law, commissioned personnel can be disciplined for a wide range of behavior under the rubric of “conduct unbecoming an officer.”

Morse received the reprimand from Maj. Gen. Jeffrey S. Buchan­an, commander of the Military District of Washington, Army officials said. Morse has been relieved from his position as chief of the Trial Counsel Assistance Program at Fort Belvoir, Va., where he oversaw about two dozen prosecutors who specialize in sex crimes and domestic violence. The office also provides training to Army prosecutors around the world.

Until the complaint was filed, Morse had enjoyed a stellar legal career in the Army. In 2012, he was appointed lead prosecutor for the worst war-crimes case to arise from the war in Afghanistan: the killing of 16 Afghan villagers by Staff Sgt. Robert Bales, who was convicted and sentenced to life in prison without parole.

The Army’s handling of the complaint against Morse caused some consternation in legal circles.

In April, as the criminal investigation was unfolding, Morse received a highly unusual written order from an Army commander instructing him and his attorneys not to speak to any potential witnesses, effectively hamstringing them in preparing a defense.

According to court records filed by Morse’s attorneys, the order was prompted by a complaint from Morse’s accuser, who was upset that the defense team had interviewed potential witnesses — a routine procedure in such cases.

Morse’s lawyers filed objections to the order with the Army’s Court of Criminal Appeals, arguing that it violated his constitutional rights to defend himself. The Army withdrew the order shortly afterward.