tax lien certificates and bankruptcy

I am a newbie and am investigating the possibility of buying some tax lien certificates. I've read quite a bit on it, but the advice on one topic seems to conflict from one source to the other--what happens when real estate subject to a tax lien certificate is also involved in a bankruptcy?. In one book I read that the certificate always has first priority--in other sources, they go to the end of the line. To clarify, I am not interested in taking possession of the property.