The reason an all points bulletin was made on Oswald was he was the only one to leave work and not return and there was an eyewitness who described him to the police. The only mistake the witness made was the description of the rifle.
Oswald didn’t accomplish any work all that morning. The boxes for the sniper’s nest was constucted that morning. Oswald’s fingerprints were all over those boxes. The wrapping paper that held the fictional “curtain rods” was left in the sniper’s next.
All three shots came from the sixth floor according to the trajectories.
And how difficult would it have been for a professional to dress the scene with that stuff, make the shots, and leave the scene in the confusion?
If Oswald did happen to be a government informant, he would have been sent somewhere during that time period and then be just as surprised as he seemed to be, pointing at his black eye and complaining about how rough the cops had been with him - and looking forward to his goverment handlers coming forward straighten the situation out.
Looks like they did when Ruby showed up.