T. J. Hooker - Season 3 Episode 15 Exercise in Murder

In pursuit of a trio of diamond thieves, who escape via helicopter, Hooker is devastated when he accidentally shoots a 9-year-old boy, leaving the youngster critical in hospital. Meanwhile, Corrigan is concerned when his steady girlfriend Jill starts acting strangely before abruptly breaking off their relationship. The girl is actually being blackmailed by the trio of robbers; and when her body is found washed up from the ocean, Stacy goes undercover at the aerobics gym where Jill worked to try and get a lead, endangering herself in doing so.