My question involves personal property located in the State of: California

Approximately a year ago I gave a fairly healthy & serviceably sound horse to a friend with the verbal agreement that she would give him back to me if she couldn't take care of him properly. She has continually sent me text messages telling me he is unridable, lame, etc, has said my vet has told her not to ride him, that she cant afford him, that she doesn't know what she's going to do about him, that she can't keep weight on him, etc. I became concerned and asked my farrier, who also tends to my friend's horses feet, including the one I gave her, how the horse was doing. He said he was very thin and had no shoes on even though the friend agreed to keep him shod for his health & well being. I showed him a picture of the horse as he was before I gave him to the friend, he said "well that's not how he looks now! His ribs are very prominent & he's skinny." Becoming more concerned, I called my vet, the one my friend said told her he was unridable (on another occasion she said that same vet told her he could only be ridden once a week by a light rider) and was told by the vet that she had not seen the horse in over 9 months & that she never told them the horse was unridable, or had any other rider/riding limitations.

Here's where it gets fish(ier) - I sent the friend a text telling her that since she could not take care of him properly and that she had stated she couldn't afford him, I wanted him back. She said NO! After sending me texts saying he was unridable, that she couldn't afford him, that he was not keeping weight on, etc, she now says I can't have him back.

My question is, how can I take him back without getting into legal trouble? I have a bill of sale showing that I bought him & I have witnesses to our verbal agreement about how she was to give him back if she couldn't take care of him. I have the texts she sent saying she can't afford him, plus the testimony from the farrier & the vet, plus pictures of how he looked before I gave him her. Can I just go get him, citing that she has violated our verbal agreement? Or will that put me in legal hot water?

Thanks in advance for any advice you care to give, and yes, I know I should have put our agreement in writing.