A problem with the digitizer on an I-9305 topic

I got an I-9305 yesterday.
On this device the touchfunction won't work. I still can use a mouse in recovery. In the OS itself there is now mouse.
I thought the one who got it before me had tampered with the devices internals but the screws are all without any scratches.
Could he/she had flashed something wrong on to this device and if so can it be "repaired"?