When the police issued the above photo-fit image last year, they received around 100 phone calls from the public.
A number of those phone calls led them to the 48-year-old man they now have in custody - someone who has spent 20 years as a police officer, acting more as a traffic officer than a criminal officer.
He left the police force in 2013 and has since gone on to work in the security industry in Switzerland.
A large number of guns and grenades have been seized from properties linked to the man since his arrest.
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Reforms will mean perpetrators are ‘properly punished’, the Government said.
Zaine Grieve fell ill in Aberdeenshire at the weekend.
Ministers have said the European Arrest Warrant had helped apprehend thousands.