There's no way to know whether they "found/collide" their own Bitcoin, unless people report they lose their Bitcoin on 100% offline device and physically secure.
But i wouldn't worry since 2^160 of possible Bitcoin adress take very long time to brute-force (ignoring Quantum Computing in this case) and your Bitcoin should be safe unless the wallet has poor PRNG(Pseudo Random Number Generation), CMIIW.
These people aren't after other people's bitcoins specifically, they're after "special" addresses that were generated oddly.