How large a gap in both space & time should a cadaver dog be permitted between source & alert? Would a delay in alerting or a misinterpreted source of alert have an adverse effect on the collection of possible forensic evidence?
Having looked at the 'problem' highlighted it seems there isn't one.
The collection of forensic evidence from the area of the couch had nothing to do with Eddie the cadaver dog's alert. The forensics were collected after viewing the filmed alerts of Keela the blood dog. She was used during the collection process also to make sure nothing was missed;
they watched the films of the searches performed by
the dog specialised in detection of human blood so that they obtained an understanding of the area from where the tiles should be collected and how many tiles they should collect.
After seeing the images and in agreement with the officers of DIC of Portimao it was defined that the undersigned should proceed with the recovery of four tiles. It was also defined that this operation of recovery of the tiles would also be filmed.
After the recovery of the four tiles and the skirting board
the dog specialised in the detection of traces of human blood was put into the area from where the tiles had been recovered, the English police officer who coordinated the movement of the dog, Martin Grime, having informed the undersigned that they should proceed with the recovery of another piece of tile that was close to the area from where the tile identified as number 1 had been lifted, that terminating the recovery of the tiles signalled by the dog.
http://www.mccannpjfiles.co.uk/PJ/5A_EDDIE-KEELA.htm
