BATON ROUGE, La. — The children of a black man gunned down by a white police officer in Louisiana’s capital sued the city Tuesday, claiming the shooting fit a pattern of racist behavior and excessive force by its police department.

Lawyers for Alton Sterling’s five children filed the wrongful death lawsuit in state court against the city of Baton Rouge, its police department and police chief, and the two officers involved in last summer’s deadly encounter. Officer Blane Salamoni shot Sterling six times during a struggle outside a convenience store where the 37-year-oldselling homemade CDs.

The Justice Department investigated Sterling’s shooting and announced last month that it will not file charges against Salamoni or Officer Howie Lake II, who also wrestled Sterling to the ground but didn’t fire his gun.

The lawsuit claims Sterling’s shooting was the product of poor training and inadequate police procedures. It also cites two instances in which Baton Rouge police officers allegedly sent racist text messages to colleagues.

‘‘The City of Baton Rouge has a long standing pervasive policy of tolerating racist behavior by some of its officers,’’ the suit says. ‘‘There have also been multiple verbal racist comments by officers reported to the department. This tolerance of such behavior directly leads to the mistreatment of individuals of African-American descent.’’

ASSOCIATED PRESS