A prosecutor says French authorities have detained a second man in the grisly shooting deaths of a British-Iraqi man and three others 18 months ago in the Alps.

Annecy prosecutor Eric Maillaud told reporters Wednesday the crime hasn't been solved.

Maillaud provided new details of a 48-year-old man detained a day earlier, calling him a weapons collector and a former municipal police officer who left his job last year. Police raids turned up weapons including vintage guns, a grenade and mortars at his home.

A friend was also detained. Maillaud said the two may have links to illegal weapons sales or trafficking.

Authorities are pursuing several possible leads behind the killings of Saad al-Hilli, his wife, an elderly relative and a French cyclist in a wooded area in September 2012.