The Ambassdor bridge crossing has always been a <deleted>. And I have heard anecdotally that border guards are getting more agressive with detaining US citizens.

I would start by contacting one or both Senators offices and your congressman/woman. You could also contact the Michigan ACLU http://www.aclumich.org

I would also write a point form description of what happened. Just the facts. no extraneous language. Also get the three other people to do the same. Include details, like are all of you US citizens? What was happenning with them as you were being detained, searched and confined?

Good Luck