Realistically, you have no chance of recovering money from someone overseas.
There are 2 ways of looking at what you do with his possessions. Firstly, following the law, I'm not 100% sure what that is and the 2nd way is the practical way, which is what I recommend.
Clean the apartment and relet it. Keep any of his possessions you want and dispose of the rest.
If he ever gets in touch, do not give any details of what you have done in writing. Your position is he left nothing in there, he owes you rent, cleaning fee and utilities (which you can justify), if it gets legal with police or lawyers (which I very doubt) you state nothing was left and ask for your money.
I suspect you will never hear from him again, learn from this, always take 2 months deposit and get right on it when they are late with rent. Trust your instinct on tenants.