Until a year ago Micah Xavier Johnson – the suspected Dallas sniper who killed five US police officers before being killed by a police robot on the night of 7 July – served in the US Army Reserve. But his military service ended after he was accused of sexually harassing another soldier, who told her superiors Johnson may have had mental health problems.

Johnson's military career began in March 2009 when he joined the US Army Reserve – the part-time forces who supplement the US Army, along with the National Guard. Johnson served in a troop programme unit in Seagoville, Texas for four-and-a-half years. He was then deployed to Afghanistan in November 2013 as part of Operation Enduring Freedom, serving one tour of duty in the country.

Whilst in the army reserve, Johnson specialised in carpentry and masonry. The New York Times noted that nothing in Johnson's records suggests that he saw combat or was wounded. It is unclear whether he received advanced firearms training, according to CNN executive editor Ram Ramgopal, citing two defence officials.

An unnamed female neighbour said the 25-year-old kept multiple guns at his home, in the Dallas suburb of Mesquite, where he lived with his mother.

"He was military, I'm not sure if he was still in, so he owned a lot of guns," she told the Telegraph. "But he seemed a calm, normal guy. There was never any problem.

"He was protective," she added. "He'd ask me if I was OK when I was on my own. When we were out we'd watch each other's houses. He always said 'hi'. "I never saw him outside with a gun. He did a lot of walking, exercise, around the neighbourhood."

Johnson received several minor medals and decorations which are given to members of the US military who serve in active duty, including the Afghanistan Campaign Medal, the Army Achievement Medal, the National Defense Service Medal, the Global War on Terrorism Service Medal, the Army Service Ribbon, the Armed Forces Reserve Medal and the Nato Medal. None of Johnson's medals were awarded for acts of bravery or heroism.

Johnson's military career came to an abrupt halt in May 2014, after a female soldier serving in his unit accused him of sexual harassment. According to the Guardian, in a court filing Johnson's accuser suggested he get "mental help" and asked for "a protective order against Pfc [private first class] Johnson pertaining to myself, my family, home, restaurant and any other place of residence I may reside at".

Johnson was subsequently sent back home, with the army recommending he be dismissed from the reserve force with an "other than honourable discharge", according to Bradford Glendening, who was Johnson's legal representative at the time.

Glendening said the guidance to dismiss Johnson was "highly unusual" as the US military usually provides counselling before taking disciplinary action in cases like these. Despite facing dismissal in September 2014, Johnson eventually received an honourable discharge from the Army Reserves in April 2015, for reasons not known to his lawyer.

"They didn't like him, that was very clear from talking to his commander," Glendening told the New York Times.

During a search of Johnson's home, authorities found ballistic vests, rifles, ammunition, bomb-making equipment and a diary of combat tactics. Dallas officials believe Johnson acted alone.