The Hillingdon Files

DCI Greg Richards, having moved away from the metropolitan area to the more relaxed confines of Bournemouth CID, finds himself at the hands of a money laundering syndicate. This syndicate has kidnapped his partner and her sister because of their knowledge of a not-so-well-hidden computer file that can expose a multibillion-dollar scam being played out, unknown to them, on legitimate enterprises.
Aided by the girls' cousin, Richards embarks on a torturous route to track the women down. The evidence takes the men to Latvia, where they have managed to pinpoint the women's location. The trouble is that the Eastern European drug runners who are holding them don't seem to be the types to just let them walk away.