CORALVILLE, Iowa — First responders in Johnson County are mourning the loss of one of their own, Sgt. John Williams of the Coralville Police Department.

Officials say Williams died Sunday from a medical issue while he was on patrol. The Iowa Division of Criminal Investigation says Williams’ death happened around the same time as a shooting involving a 3-year-old boy, who later died, but says it is not directly related.

Williams was a 28-year veteran of the department and is survived by his wife and four children.