Do You Know Murphy the Little Lost Dog in Maine?

I was on a walk with my dog today in downtown Portland and we were joined by a small white dog who tagged along for half a block before I began to wonder why he didn't have an owner chasing maniacally after him. I checked his collar and it says "MURPHY" on one side and "Crap, I'm lost. Call my mom" with a number on the other. When I tried calling the number, I got this weird tone and a "user busy" message:

I texted the number and called it multiple times every hour since finding him around 5pm, all to no avail.

If you know Murphy, his owner, or have any other lead on how to get this little guy home, please reach out!

I've posted his photo on Maine Lost Dog Recovery on facebook and plan on taking him to the vet or humane society unless  I get a tip on where he belongs. He's a sweet, mostly quiet boy until someone closes a door down the hall, at which point he erupts barking, which is a primary reason he can't stay at my place longer.