The actor/director's ex-girlfriend Oksana Grigorieva accused the star of attacking her and knocking out a tooth earlier this summer (10), prompting officials to investigate the matter.
They have also been investigating Gibson's claims that the Russian singer was attempting to extort money from him. Sheriff's spokesman Steve Whitmore tells the Los Angeles Times that study will also be completed soon.
The findings will be passed to the Los Angeles County District Attorney's office. Lawmakers will then decide whether to press charges against Gibson.
Investigators have poured over emails, texts and leaked audio from a fiery phone chat between Gibson and his ex.