You're right: he put himself in a big bind. If he claims self-defense, he'll have to testify. If he does, the prosecution could cite the retained passport and the lie about assets to impeach his credibility.
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.