Not genetic, and probably a common-or-garden variety of misbehaviour ; most kids at some stage, and around this age, discover the possibility of lying and of stealing, and many try it out. What is needed is firstly a calm chat with the kid, explaining that both lying and stealing are wrong, and asking for his explanations of why it's wrong ( rather than asking him to explain why he did it, which he's far less likely to be able to explain ). Explore with him how he would feel if someone stole from him, or if you or someone else lied to him about something important to him. Personalizing it this way makes it easier for him to understand why it is wrong and worth avoiding.
And take this opportunity to state your basic house rules, which should include not stealing, or lying and other significant rules ( not petty stuff ) and the consequences for any time he breaks such rules. Corporal punishment doesn't work, and merely teahes that its OK if you're the more powerful one, to use vilence to get what you want. The punishments should include defined penalties, like losing TV or cell-phone privileges, or access to computer games, or whatever else he really values, for longer perios according to the seriousness of the breach of rules or repetitition of the offence
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