Accused of stealing gold

Before starting, I'd like to say that I used to steal some money and used to lie. But since a year or two, I've never done anything like this. I'm a 17 year old guy. I live with my family (my mother and three sisters, my dad lives abroad). I visit to my dad with my family every year. This past year (2016), my mother lost a gold pendent. She said that I have stolen it for money/to sell it for money. My father, my sisters beated me alot for that (all this happened in abroad, Saudi Arabia). But I swear to God that I haven't stolen it. And now recently in India, my sister lost a gold chain with a locket in it. This time also the beated me alot for the same reason. My mother told me that she would file a complaint in the police against me. First, one can't sell gold to ANYONE in Pune or anywhere else without a certified bill of it. Second, I'm underage so why would any Jeweler believe me. Even if assumed that someone would sell in the black market, they would first enquire about it (right ?). Also I have very little friends and all of them are very good and have a very respectful family background. I want to know if she files a complaint in the police, what will happen to me ? And what can I do ? Please help me out in this case. Thank you for the help in advance