Can be tricky depending on where it is in the process. If it has been bank owned for a few months, it may show up on the tax records. The way you would know, is that a financial institution would be listed as the owner. This site allows you to search NJ Tax records for free: www.njactb.org
Also, you can search the country sheriff website. You'll want to look under "civil process" or "foreclosure" you should be able to search on the site specific address, and you'll be able to see when they got foreclosed or where they are in the foreclosure status.
If they are listed they can be found on either a bank's or third party servicer's website who is handling the asset or a good Realtor can help you find out.
Hope that helps.