Despite Mel Gibson's claims of Oksana Grigorieva trying to extort money from him, evidence keeps mounting to the contrary. Grigorieva won't need to make too much of an effort to defend herself - turns out, there may be plenty of witnesses to corroborate her claims of abuse against Mad Mel. Last year in Costa Rica, for example, the two were at a party with Grigorieva's son by Timothy Dalton, Alexander. The 12-year-old was playfully jumping up and down, trying to knock Mel's cigarette out of his mouth. Mel exploded, according to TMZ, and threw the kid on a table. The incident was raised during a May mediation, during which the couple unsuccessfully tried to work out custody and finances surrounding their daughter. Mel's people claim Alexander fell on his own while jumping around at the party. If it happened, then there were plenty of adults and other children around to act as witnesses for Mel or to expose him as the rageaholic he's being portrayed as in the media. And Radar reports even more ammo in the form of witnesses on Grigorieva's side, stemming from his alleged attack on her and daughter Lucia back in January. Radaronline.com has published a picture of the baby's chin, which looks like it may have a small cut - or simply an outbreak of baby acne. The punches, which Mel was taped saying she "f*cking deserved," left Grigorieva with broken teeth and now a concussion, which she sought treatment for two days after the attack. Her dentist plans to testify about the damage to her mouth; now Dr. Arthur Gordon will come forward with his diagnosis of a concussion on Jan. 8. No one has diagnosed Gibson yet, but we're pretty sure he's certifiable.