Hi
Where I take Will down the canal there is a narrowboat which has a resident rescue GSD. She's a bitch, around 6 years old, and the guy was told by rescue that she is an ex-police dog?

Anyway, he's had her about 3 months, and he's an elderly chap (not to stong on his feet)
At first, she was very friendly, loved Willis and, although she wasn't overkeen on other men talking to her seemed to be ok with me. But, for the past month she has turned really agressive. She barks really ferociously from the back of his boat at people who walk past (including us), hates all other dogs, and is turning into a bit of a tyrant. Her owner is getting worried because she is so nasty, and ties her up, but, other boaters, residents and walkers are none to happy. How can I help, what advice can I give?
I am under the impression that now she's settled in she sees it as her responsibility - but its antisocial behaviour in those particular circumstances.
Any advice?