S4·E19 Homecoming

Hooker's children come to visit their father, but the vacation is interrupted after Corrigan and another Officer unwittingly disrupt an armed race-track heist, which leaves Corrigan's fellow Officer dead. The robbers were under the pretence of being ambulance attendants, and Hooker has reason to believe that the robbery was an inside job; but the case means that his time with his cherished kids is limited.