The family of a man shot and killed by Nassau County police in a case of mistaken identity is filing an excessive force lawsuit against the county. According to reports, 23-year-old Kurt Doerbecker was shot in the back of the head last August as he climbed out of a window. Doerbecker’s family claims that authorities overreacted, sending an armored vehicle, nearly 100 officers, a police boat and a K-9 unit to apprehend Doerbecker.

Police say Doerbecker confronted officers in a threatening manner while brandishing a knife, at which point an officer fired on Doerbecker, killing him. The Nassau County District Attorney’s office says they are still conducting an investigation into the incident.