My neighbor borrowed my ladder for 3 months and when I needed it I went over to knock on his door to ask for it back. My dog followed me across the street and when his son opened the door he left it wide open and let their vicious dog out without trying to stop him and he attacked my dog and put 2 puncture wounds in his back. I called the vet and got a prescription for antibiotics which my neighbor said he would reimburse us for. I put the receipt in his box and he never responded. 1 month later I asked if they got it and said yes but it was the holidays and they were short on money. Which is not true. Now it is March and I saw them today to ask him again and he tells me I trespassed on his property and is not responsible for his dog getting out and attacking. Who's liable?