Somebody broke into our car!

On Monday we went to the car and then we saw the all the stuff which usually are kept in front spilled on the front seat... I lost my sunglasses which had more emotional value as I had bought them few years back in the States...they took Martins cable for the GPS...the worse thing is that there are no signs of somebody breaking in...how these people got inside no clue . The worse thing is that it's the second time that somebody breaks into the car and last time the car was parked on the same street...
Last time they took the chains...
Anyhow but guys Brno city centre is not safe!