Back during the time that your grandfather was a cop, the Basque area around Eibar in Spain was a hotbed of firearms production, most often producing copies of Smith and Wesson revolvers. The quality of the guns ranged from very good to very dangerous and I'm not really sure how to tell the difference if it's not immediately obvious.
Sometime in the mid '50s or maybe the early '60s, Smith and Wesson got the US government to really crack down on imports of the Spanish revolvers and they pretty much disappeared from the market.
I should add that arms production in Eibar was most definitely not limited to making copies of other companies' guns. The region has a very long and storied history of arms manufacturing.
Here's a link to the Eibar Arms Industry Museum's collection of small arms.
Over at gunboards.com, there is a Spanish firearms forum with a few folks who are walking encyclopedias on the subject.
