Took a little longer than I thought, but I used the time to chuck in a number of other bug-fixes and minor UI additions. New public release is
here, video diary
here.
I'm going to try and revisit the 'detective work' mechanics again, see if I can't iron out some of those wrinkles. If anybody has suggestions for gadgets or perks they'd like to see in the meantime, this might be a good time.
In the longer term, I'm a little worried that the timescale for investment projects is likely to be too long relative to the spacing between crime events. Base facilities in X-Com typically complete in no more than a month, but factories and schools could take a year to construct. Maybe you'd enter a sort of 'time acceleration' mode once all the current gang-bosses are behind bars, allowing a couple of months to pass before another breakout/crimewave occurs? (Think what you could do with 18 months of clean streets.)
I actually need to implement a prison/trial/sentencing system for that, of course...