There were no signs of illness, no signs of injury, nothing to indicate anything was amiss. One moment, normal dog. Next moment, dead dog. The entire process took about ten or fifteen seconds. Several people witnessed the actual howl followed by the"keel-over." I was outside within moments to see what the commotion was all about, by which time the dog was completely dead, no twitching, tongue out, eyes opem, basically looking like it was just sprawled out and relaxing as it normally does.
The neighbor said the dog is, or was, about nine years old.