I am very sorry for you.
The drawback of folding bike that are easy to carry is that they are as easy to be stolen !
For the Brompton in Europe its a nightmare because there is a high demand for used Brompton and the used price are high, so its probably the best deal for thief.
But other folding bikes, even if less attractive because of lower value or less known, are also stolen.
The rule with a folding bike is to never leave it outside, always take it with you.