We got a new puppy about 3 weeks ago.  A couple was turning him into the Humane Society after taking him in for 2 weeks.  He was a stray and no one was answering to their ads and posters.  We think he's about 14-15 weeks old, and we aren't sure what he is.  We know he's brindle... and looks like some Black Lab.  Boxer or Pitbull?  Please help...

Here is a link to a few pics... I know he's just a puppy, but we are really interested in what breed he is!  Thanks!

http://s34.photobucket.com/albums/d134/Kisses9370/Stud/