Eastwood's first collaboration on a feature with Anjelica Huston as both director and co-star. Coincidentally, he'd earlier portrayed the actress's father John Huston in White Hunter Black Heart (1990).
Famous for playing Dirty Harry and sometimes other copes, portraying an FBI profiler in this movie, this is the final cop film (to date, March 2013) of Clint Eastwood where he plays some form of detective.
After Terry discovers that the killer takes mementos from his victims, the 'blowup' of the killer taking Gloria's earring is taken from a completely different angle than the previously seen surveillance tape (not to mention so clear that the other detectives could never have overlooked it).
When Jasper Noone dives into the oily water on the wrecked ship, bullets hitting the water stir up mud and such. Afterwards, Noone doesn't have a speck of oil, mud, or any other type of filth on him.