If your network is clean. Then there will be left only one problem you have experienced. One of your relatives took your private key and made the money transfer. There are no other option.
This is also the thing on my mind.If there were no phishing,clean pc,clean network then this is also a possible thing to happen on which there might be some relatives who are
aware on its privatekeys.Its odd to see that 3 hours after creation its being hacked unless those keys are exposed or miscopied anywhere.