When did Detroit drop out of the top 3?
When the last person worth mugging moved to the burbs.
Here's a good site for per 100,000 crime rates of the largest cities. Baltimore leads the way in murder, at 42/100k, followed closely by Detroit at 41.4/100k, the St. Louis, DC, and Newark. Motown also leads the pack in aggravated assault and car theft.
Next to Camden, NJ, Detroit is the scariest place I've ever had the misfortune of visiting.
After everybody boarded up the town and left.