A Huntsville police officer says he was acting in defense of himself and others when he fatally shot a suicidal man this past spring.

Officer William Darby is asking a judge to grant him immunity and bar the Madison County District Attorney’s Office from prosecuting him for murder.

“For an officer to be convicted of Murder resulting from an on-duty shooting, the facts of the incident would have to be so bizarre that there is no rational explanation for the officer’s actions,” Darby’s defense attorney Robert Tuten wrote in court records on Friday.

Madison County Circuit Judge Donna Pate scheduled a hearing Feb. 28 at 1:30 p.m. Prosecutors haven’t yet responded to the defense request.

“The defendant contends that, acting in his official capacity as a Huntsville Police Officer, he was acting in self defense and in the reasonable defense of others pursuant to ... (Alabama law),” Tuten wrote in a motion for immunity.

Darby killed 49-year-old Jeffrey Parker on April 3, 2018. Parker called police that day, saying he was suicidal and had a gun, the authorities said. Officers said they briefly spoke to Parker at the scene on Deramus Avenue. Parker didn’t comply with Darby’s orders to drop the gun, the police department said, and Darby fatally shot him.

In August — months after the police department’s internal review board cleared Darby of wrongdoing — a Madison County grand jury indicted the 25-year-old officer on a murder charge. District Attorney Rob Broussard said he was "gravely concerned" about Darby’s actions after seeing body camera video of the shooting. His office is prosecuting Darby.

In their motion, the defense argued that Darby’s actions didn’t violate Alabama law, which says, a person who is justified in using deadly physical force is immune from criminal prosecution and civil action.

Alabama law says a person is justified in using deadly force, “if the person reasonably believes that another person is using or about to use unlawful deadly physical force.” The defense also cited Alabama’s Stand Your Ground law, which says a person acting in self-defense doesn’t have a duty to retreat.

“...the Defendant acted in accordance with Alabama law, and within the policies and procedures established by the Huntsville Police Department,” Tuten wrote in court records.

Huntsville Mayor Tommy Battle and police Chief Mark McMurray have defended Darby, saying he isn’t a murderer.

The city has refused to release to the public the body camera videos or other records related to Darby and the shooting. The city council — at the urging of the mayor — voted to pay for Darby’s defense.

Darby, a 25-year-old from neighboring Morgan County, was on the police force for about two years at the time of the shooting, the department said.

Judge Pate has issued a gag order that prohibits public comments by lawyers and law enforcement regarding the case. Darby is represented by Huntsville attorney Robert Tuten. Madison County Chief Trial Attorney Tim Gann and Assistant DA Tim Douthit are prosecuting.

Darby’s trial is scheduled April 8.