Dog pooping in crate

Good evening. I am going to post this tonight and then go to bed. I will check the answers tomorrow. Thanks in advance.

We got our dog from the Humane Society in Kerrville, Texas last year this time. She was a four year old Shih Tzu. When we got her she was very well potty trained. Whoopee.

We started out with a crate and when we were away or went to bed she went in the crate. She never had accidents in the crate or in the house.

I think we messed up. We started letting her sleep with us and not be in her crate when we left. All was well for seven or eights months. Then one day she pooped in the motor home while we were gone. We watched her closely and no problems until the next time we left her alone for less than two hours. She pooped again.

Now we have started putting her in the crate when we leave and she is doing it in the crate. We are not angry with her because we think we have caused it. How do we fix the problem?

She is a wonderful little girl and at least she messes in the crate and not the motor home.

Thanks for your replies.

By the way, we have not yelled or screamed at her. I pointed at it and said bad girl and that was it.