Have you read his sequel to once & future titled sword in the stars?
I think you might be confusing James Patterson with someone else? I don't think he wrote that. 
that's possible. he wrote the alex cross series, correct?
Yes, he does the Alex Cross books and Women's Murder Club. 
A number of his books have been adapted for film. For example, miracle on the 17th green in 1999
I havent seen that one. I watched the ones with Morgan Freeman playing Alex Cross, and I saw the one with Tyler Perry playing Cross as well. 
i have read one of the alex cross books a long time ago but never any other of his novels
He's actually doing a lot of children's books these days. My son likes them. 
what makes you suspect he doesn't write his own books?
A lot of his books have 'co-authors' listed. And he can have two or three books come out in a single year. I think that maybe he comes up with the idea and does the outline, but the co-authors do most of the actual writing.