I'm Andrew, a community manager here in Trulia Voices, and so can speak on Trulia's behalf.
We currently rely in a police departments to release their own crime data, and I do not believe that we cover Westerville, OH at this time. We are always adding new cities, especially as police departments continue to get better at releasing their data.
The best thing to do would be contact the Westerville, OH police department, which you can do here: http://www.westerville.org/index.aspx?page=162
Let me know if there's anything more I can do to help,
Community Manager, Trulia Voices