Hoo, Boy
It may put your mind slightly at ease to think about all of the other reasons, besides reasons involving criminal intent, that an individual may be up at night instead of during the day. Many students study for long periods of time at night, or have most of their fun at night. A lot of people work third shift jobs, and this is the level of employment that a former convict is likely to be able to secure right away... a factory, or similar production work. Third shift typically pays 10-25% more than first and second shift in places such as this.
For my part, my sleep schedule is usually from 6am-2pm. I dislike mornings intensely, and I prefer to be active at night largely because most other people aren't. I live in a neighborhood that's frequented by missionaries from the Mormon and Witness faiths, as well as door-to-door salesmen, and I've had trouble in the past with a former landlord and the police (parking tickets that I never saw, nor received any notification for). I prefer being up and about when I'm less likely to be bothered by the-gods-know-who. I don't drink, or smoke, or do drugs--never have--I don't party, or have a lot of visitors of a disruptive nature (or otherwise) and aforementioned parking tickets are more or less the most damning legal issues I've ever been involved in.
It is important to remember that the people moving in are FORMER convicts. They aren't 'convicts,' convicts live in prisons behind concrete walls, searchlights, and barbed wire. Former convicts have served their debt to society, and if they are believed to be of any danger afterwards they are monitored, otherwise they're free to attempt to resume a normal life... which many of them manage to do, one of my housemates amongst them. I've lived in the same house, with no locks on the bedroom doors, for ten months now, and I've had no problems whatsoever with the convict one room removed from me (whereas the clean-cut individual one more room removed from me is obnoxious, self-centered, and domineering; it is because of his presence that I am currently looking for a new place to live).