The lawsuit seeks more than $10 million in damages against the Kansas City police board and DeValkenaere. The detective, who has been suspended for more than a year, is awaiting trial on first-degree involuntary manslaughter and armed criminal action in Lamb’s death.

It wasn’t immediately known whether DeValkenaere has a lawyer who could comment on the lawsuit. He’s represented in his criminal case by a public defender, who would not represent him in the lawsuit.

The police department declined to comment on the lawsuit, citing policy against commenting on pending litigation.

Court records in DeValkenaere’s criminal case say he and another officer were investigating an earlier disturbance involving Lamb’s truck and another vehicle when they went into Lamb’s backyard on Dec. 3, 2019. DeValkenaere said he shot Lamb, who was still in his truck after backing it into the garage, after Lamb pointed a gun at the other officer.

A police investigation into the shooting said Lamb’s left arm was hanging out of the truck and a gun was found on the ground beneath his hand.

But prosecutors and attorneys for Lamb’s family say Lamb was right-handed and did not have full use of his left hand as a result of an injury sustained in 2015. The lawsuit accuses Police Chief Rick Smith of assigning a former supervisor of DeValkenaere’s to conduct the investigation into the shooting and failing to tell prosecutors of the supervisor’s connection to DeValkenaere.

Lamb’s family has doggedly sought answers to questions about his killing, meeting with then-President Donald Trump last summer along with other families of people slain by police or while in custody. Lamb’s children are being represented by S. Lee Merritt, a Texas civil rights attorney who represents several other families of Black people killed by police.