During a police investigation all sorts of material is amassed. Statements, CCTV images. photographs,forensics, and, in some cases, dog alerts. Detectives analyse the material as they go along. Some of it leads in one direction, some in another. Some of it requires confirmation such as appeals for further witnesses. Not all of it will be used as evidence in any subsequent court case, but all of it is potentially important until eventually detectives decide to follow one particular line of inquiry. Until then all the material remains possibly important. Anyone who thinks multiple dog alerts would be completely discounted because no definitive forensic evidence was found to support them is fooling themselves imo. They remain a part of the picture until evidence is found proving that they were wrong.
Grime himself acknowledges that handler-bias can influence a dog's reactions, and I know Alfred has found a study (nothing to do with Grime) where precisely that phenomenon accounted for all a dog's reactions.
Handler-bias: the
findMadeleine stickers on the back of the Renault Scenic.
The disproportionate time spent in apartment 5a compared with any other apartment.
The re-examination of clothing (in the gym) present during the inspection in the villa, but not evincing any interest from Eddie.
The interest in the toy, only after it had been hidden, not while he could see it, sniff it and play with it.