How do you know if your rabbits been attacked by a cat, if he is missing in the backyard how do you know if he is still alive?

You don't. Most likely it was not a cat (unless it was a bobcat). Was the rabbit running loose in the yard or in a pen? If loose, then likely a dog, coyote or even a large hawk/eagle could have taken the rabbit for dinner. If in a pen, likely a dog broke the pen and took the rabbit and killed it.

You don't unless you witness it. You ask yourself how you could take such poor care of a helpless creature, not protect it from danger.

They dig holes and escape very rapidly. Or depending on what predators live in the country you are in, on of those might have had him. If you leave food out for him, he might come back. WHen I was young my sister lost her rabbit. It lived all summer in a field, and we caught it again months later by holding a handful of leaves for it to eat.

Domestic rabbits belong INDOORS !!! Rabbit.org.

Rabbits actually turn feral within a very short period of time. In all likelihood he has just returned to his wild roots.

Start looking/investigating for your self, as YA won't do your leg work for you.

It was your responsibility to keep them safe by whatever means necessary, as there maybe numerous other predators that may have gotten them as well, because you failed to keep them safe from harm at all times and/or supervise them.

New account alert...

If he's missing then a hawk, owl, fox, dog, coyote or raccoon got him. A rabbit is almost the size of a cat, cats don't drag off their prey like the others do. And they can't eat the entire rabbit either - they have a hard time just putting down the entire contents of a standard 6 oz. can of cat food.

Is your rabbit still alive?

if the cat tells you he attacked a rabbit