With the active help of his "IT genius" friend, the deduction of a neighbor's address isn't very far-fetched.
Often the IP will clearly identify a regionally-specific ISP and even a particular community. And once recognized as someone local, there were probably just a few suspects from vague hunches about who seems a little angry/fidgety/pranky.
Maybe the neighbor leaves their wifi open: borrow access one day, see what the public IP is.
Maybe the neighbor corresponds via email with Traynor or the 'genius': check email 'received-from' headers; include an HTML email image bug; tempt the target to click a unique link.
Often the IP will clearly identify a regionally-specific ISP and even a particular community. And once recognized as someone local, there were probably just a few suspects from vague hunches about who seems a little angry/fidgety/pranky.
Maybe the neighbor leaves their wifi open: borrow access one day, see what the public IP is.
Maybe the neighbor corresponds via email with Traynor or the 'genius': check email 'received-from' headers; include an HTML email image bug; tempt the target to click a unique link.