At one point Clint Eastwood is out in the woods practising his shooting with his new .44 auto-mag pistol. While he's doing this, a car pulls up and a black male begins to get out with a shotgun. (We later learn that this is his partner). As the man with the shotgun is opening his door, if you look at the reflection in the car window, you can clearly see the reflection of a man with a camera and another man standing next to him.
Clint Eastwood's friend Horace, the black male first seen sneaking up on him with a shotgun is also in other movies with Dirty Harry. His first appearance is the first "punk" where Harry gives his famous "Do you feel lucky...?" line to. He also appears in the Enforcer as Mustafa, the black militant leader. He is also in the second, Magnum Force, playing a pimp who is followed in his Cadillac with tiger skin seat off the freeway by the corrupt traffic cops. He talks a little to the officer and then, like other dodgy characters in the film, is shot a few times.