Law enforcement sources tell TMZ that Berry was in her kitchen Sunday when she looked out the window and saw a man staring at her, holding some sort of book.
Berry ran to the phone, called 911 and the chase began.
An LAPD helicopter circled Berry's home and the area nearby for nearly 30 minutes, trying in vain to locate the trespasser. A number of officers in squad cars were on the hunt as well.
Sources say the suspect is the same man who jumped Berry's security wall on Saturday, triggering the first 911 call.
Law enforcement believes the suspect is an obsessed fan, possibly hell-bent on getting her autograph, but they haven't ruled out a renegade paparazzo.