I was just reading the article in the "El País" newspaper.
It seems they were after those JW's who sold properties and persuaded them to invest in their scheme, in the shape of an investment company called "Rural New Life y Mutua Mas Vida". Looks like they "re-invested" the funds in properties. (It mentions estates in Marbella and Lanzarote, tourist resorts). I bet that, in the craze of the real estate market back then, some deals were initially profitable, but soon they were caught in the curve.
The 1300 may well be solely the number of people that participated in some sort of class-action lawsuit, or identified victims by the court. The number of those who actually donated may likely be much larger than 1300. In that scenario, this story gains more plausibility.
Eden