STILLWATER — A Minnesota sheriff’s deputy goes on trial this week in the April 2018 fatal shooting of a suicidal man with a gun who allegedly told police he wanted to kill himself as they tried to get him to surrender.

Washington County Sheriff’s Deputy Brian Krook has pleaded not guilty  to second-degree manslaughter in the death of Benjamin Evans, a 23-year-old emergency medical technician and aspiring firefighter.

Krook was among officers responding to a report of a suicidal armed man in Lake Elmo, about 19 miles (30 kilometers) northeast of Minneapolis. The Minnesota Bureau of Criminal Apprehension has said that when officers arrived, Evans was holding a gun and saying he wanted to kill himself.

Krook told a grand jury he had no choice but to shoot Evans because Evans aimed a gun at him and another deputy, but prosecutors say Evans didn’t aim at officers and repeatedly said he didn’t want to harm them.

Prosecutors said another deputy didn’t consider shooting Evans during the roughly 40 minutes they tried to negotiate his surrender.

According to a filing by defense attorneys, Krook told the grand jury that Evans’ movements with the gun were getting “close to where it’s pointing at” deputies. Krook said Evans turned his head toward Deputy Michael Ramos, “so I fired, um I just fired.”

Krook gave a similar statement to state investigators, saying he believed Evans’ gun was pointed at Ramos, the defense said.

Ramos told the grand jury that Evans “didn’t aim at us, but kind of flagged us. Like when moving the gun, just kind of points in our direction. I don’t know if it was intentional or not.”

Defense documents also cite a letter Evans wrote, apologizing to the first responders who would have arrived after he killed himself.

Jury selection in the case began Monday and opening statements are expected later this week. Evidence is expected to include squad car video and video from Krook’s body camera. Potential witnesses include Evans’ father, several law enforcement experts, sheriff’s deputies who were at the standoff, and others. It’s not yet clear if Krook will testify.

The defense has said the standoff began shortly after Evans’ girlfriend rejected his plea to marry him. Prosecutors are seeking to limit testimony that would indicate Evans was suicidal in the days before his death, as well as evidence about his blood-alcohol content when he was killed.

Krook is the third Minnesota officer in recent years to be charged in an on-duty killing.

Former St. Anthony officer Jeronimo Yanez was acquitted in the July 2016 killing of Philando Castile, and former Minneapolis officer Mohamed Noor was convicted in the July 2017 shooting of Justine Ruszczyk Damond.