No news stories on this, so bear with the Tweets.
Senator Jeff Merkley went to a shuttered Wal-Mart in Brownsville, Texas that has been turned into a detention center for children separated from their parents a couple of hours ago to try to get access to the kids and check on their care. The sitting U.S. Senator had the cops called on him and was turned away.
He has posted a video of the encounter on Facebook.
Not a lot of other details yet, will update as available.
I think this Twitter user speaks for all of us.