if you installed the .tgz package using pkgtool or installpkg, like slack is made to do, just use the pkgtool again, go to 'Remove Package' and it will show a list of installed packages. Select Tripwire, click OK and it's gone.
For non .tgz packages, try installing the program checkinstall. Then you'll untar the tar.gz package (or any other package), use ./configure --options, make but next you'll substitute 'make install' with 'checkinstall'. It will create a .tgz package itself and add it to your pkgtool list of packages for easy removal. Nice tool to have.