But the seal on the washing machine door should not have prevented an alert Red. It didn't prevent an alert at the car. There was only one key fob in the car, but there were several items of clothing which were alledgedly contaminated in the villa - even if they were in the washing m/c.
Was there a PJ list of the clothing taken from the washing machine do you know? Just curious?
A seal on a washing machine needs to be water tight, so it's a given that it would be airtight. Any seal on a washing machine would also be made from impermeable materials so the dogs would not have detected anything through it. How do you think test materials are transported for testing cadaver dogs? In non permeable containers or they would be alerting all over the place whilst in transit.
Dogs are trained not to scent impermeable membranes. When providing training samples for dogs such odours have to be contained, in gas impermeable containers. This has presented problems in that trainee dogs might begin to identify the scent of container (neoprene type etc)
By the same token an EVRD which responds to human trace odours only will not identify odour of impermeable membrane around a body So, with right 'wrapping' or containment, dogs can miss cadaver as not trained to scent impermeable membrane.