black rottweiler walking alone on street at president/ fifth

cat

hi - about half an hour ago(1:30 p.m.), i saw a black dog, a rottweiler, roaming the streets first at sixth and carroll then on to president and fifth. i could not get close enough to see if he had tags ... someone called 311 and they were supposedly on the way. i know very little about dogs and the dog seemed semi-friendly but it was hard to tell. if you're near there and can take a peak or might know someone who's dog is 'missing' ... well that's why i'm posting. i tried to find him again (i had heavy packages on me and couldn't walk very fast) but could not.