Fond du Lac residents joined law enforcement officers Thursday afternoon to honor four local law enforcement officers who died in the line of duty. Fond du Lac police officers William Prinslow, Nick Klaske and Craig Birkholz and State Patrol trooper Trevor Casper were honored during a Law Enforcement Officers Memorial Ceremony at the Fond du lac Police/Fire Memorial in Hamilton Park. Police Chief Bill Lamb says nationwide, more than 22,000 law enforcement officers have been killed in the line of duty, including 264 officers who were killed last year. In Fond du Lac, Officer Prinslow was shot and killed in 1898 while attempting to apprehend three robbery suspects. Officer Klaske died after being shot while chasing a burglary suspect in 1961 and officer Craig Birkholz was shot and killed in March 2011 while responding to a sexual assault incident. Trooper Casper was shot and killed in March 2015 while attempting to apprehend a bank robbery and murder suspect. Before he died Casper shot and killed the suspect.