Why do families of prisoners keep being subjected to insane treatment by the prison service? I am appalled and I have to agree with EX-Cons post; the explanation from the prison will be a feeble one.
The sniffer dog thing is a controversial one and Prison Widow highlighted Eddie and Keela (Cadaver dogs) who were ''wrong'' to have picked up cadaver scent during the MCcann investigation. 
The sniffer dogs cannot speak and therefore I would have have refused a police search and asked for evidence from the dog.. can anyone take a dogs word for it? The answer is an obvious one. The screws/dog handlers always say that the dog has indicated a drugs scent. I mean, come on, it is all bull crap from the word go! 
I am so sorry for the Low Moss visitor. I have no words. Just as a matter of interest, if the prison service happens to read my post; 'do the prison officers have a drugs dog line up before they go on shift? And if they do; who witnesses it and is there independent witnesses? Drug smuggling in HMP comes from all sources and whether the system likes this or not.. it includes their own. 
I am completely sickened by HMP Low Moss's actions and I would without any shadow of a doubt put a complaint in. The reply would tip toe around the houses and their drugs dog will be a international award winning sniffer dog no doubt. 
Band the word via social media and website until you get an apology and I would be goading for compensation too. The Police found no evidence of drugs on this family member and they must have been traumatised and are still very upset about the whole situation. Pardon my French but what a set of bastards!