He tells Zimmerman he has received an anonymous phone call "from somebody who gave a different version of events ... more along the lines that you tried to detain him," and recounting an argument prior to the shooting.

"You got any problems with black people?" Serino asked Zimmerman, who replied, "No, sir."

Serino told Zimmerman authorities can't figure out what would have made Martin "snap." Zimmerman said he didn't know what might have enraged the teen.

And the investigator expresses doubt that Zimmerman, who had lived in the neighborhood for three years and described himself as head of the neighborhood watch, did not know the names of the three streets in the subdivision.

"To be honest with you, I have a bad memory anyway," Zimmerman said, adding that he has attention-deficit (hyperactivity) disorder and takes medication for it.