Is this the end for Hemi?

Our beloved Hemi is missing... gone for 5 days now. At nearly 12 years of age he has had an interesting life; he's lived in many many houses [we tend to move a lot], and in 4 different towns, but he has NEVER been away so long without a postcard.
Tonight Fraz was convinced he heard a faint squeaking outside and spent a while out in the back yard with a torch, whistling and calling for the cat, but to no avail.
We have made up flyers with this handsome photo on them and have added his name to the Lost Pets database at the local petstore/vet clinic.
We feel pretty helpless other than that, and keep asking ourselves if we could have done him better. The kids did harrass him frequently, and we don't have a cat flap at this house, which sucks. Plus the neighbours' two cats hang out in our yard a lot, much to Hemi's horror. A couple of days before he disappeared I had to rescue him from the two cats who cornered him, and that must have been quite humiliating for him. He still frequents our old address, as it is only a block away, but even the old neighbours haven't seen him for a few days.

WHERE FORE ART THOU HEMI???!!?!?!