My question involves criminal law for the state of: TX

I rarely comment on this forum, but I have learned a lot. I have an incident that I would like to share. Might sound childish, but here it goes:

About 2 weeks ago, my friend was on an ATV on the side of the road. Well the cop turns on his lights and my friend takes off due to the ATV not wanting to start. The ATV did not belong to him. It belonged to another friend. Well the owner of the ATV appears at the city hall and was arrested due to warrant. The ATV is "under investigation" and have released it. The cops said that as soon as the driver turns himself in, they can release the ATV.


Can the cops do that? Is this unlawful seizure? Thanks in advance.