[A] I caught them stealing my apples, (I found them doing this); If she catches you reading her diary, she’ll be furious. I found him standing at the door = I saw him standing/He was standing at the door when I arrived; He found a tree lying accross the road. [B] I left him talking to Bob = He was talking to Bob when I left.
[[A] Con catch la acción expresada por el participio es siempre una que disgusta al sujeto; Con find no hay sentimiento de disgusto, y el objeto puede ser inanimado. [B] leave puede usarse con un participio.]
A Practical English Grammar (A.J. Thomson & A.V. Martinet) 