The family of a longtime lawman gunned down by his own colleagues last year has filed a wrongful-death lawsuit against St. John the Baptist Parish Sheriff Mike Tregre, claiming deputies should have used “non-lethal means” to quell a domestic disturbance at the lieutenant’s LaPlace home.

The lawsuit, filed Thursday in U.S. District Court in New Orleans, blames “the entire tragic incident” on a lack of training within the Sheriff’s Office and claims Lt. Nolan Anderson did not pose an “imminent danger” to the deputies who fatally shot him.

It further alleges that one of the deputies who opened fire, Sgt. Richard Dubus, disobeyed an order to stand down from a crisis management negotiator tasked with “bringing a peaceful resolution to the conflict.”

Tregre declined to comment on the lawsuit.

An attorney for Anderson’s family did not return a call seeking comment.

The shooting followed a standoff between Anderson and his colleagues on Sept. 24, 2014, at a residence on Pine Street. An investigation by the State Police found that Anderson was armed with a department-issued gun, which he fired before the authorities arrived, and that he used his police radio to threaten responding deputies.

Those deputies arrived at the home that afternoon to find Anderson holding his wife at gunpoint, according to State Police. “Several shots were fired inside the home prior to and during the deputies’ arrival,” the State Police reported.

Tregre told reporters last year that his deputies had taken “extreme measures to try to talk him down” but that Anderson “put us in a position for fellow officers to take his life.” He said Anderson’s decision to open fire left deputies no choice but to use deadly force.

“It’s a day that I never thought I would see,” the sheriff said at the time. “The only positive side in this entire tragedy is that we were able to save his wife.”

Anderson, a 25-year veteran of the force, died at River Parishes Hospital before he could be transferred to a New Orleans trauma center. No criminal charges were brought in his death.

The lawsuit claims that the crisis management negotiator, Lt. Gregory Baker, had issued a stand-down order to Dubus so that Baker “could have more time to negotiate with Nolan.”

It also says Detective Thomas Ricks “lethally shot” Anderson after he already had been “incapacitated” by the shots Dubus fired.

The deputies “could have and should have used non-lethal means to incapacitate Lt. Anderson,” the lawsuit claims.

Dubus was sued in a separate wrongful-death lawsuit in the case of Deborah and Robert Prine, a couple fatally shot by St. John deputies in 2012. Court documents show that case was settled out of court last year for $12,000.

Follow Jim Mustian on Twitter, @JimMustian.