Mason Mayer, brother of Google VP and local socialite Marissa Mayer, is facing three felony charges in San Francisco for an alleged attack on his former girlfriend that took place at his condo in the Four Seasons back in September. During the incident Mason, who has not held a job since his sister's company went public back in 2004 and lives in the same building in which she owns a $5 million penthouse, allegedly punched and beat his then-girlfriend before threatening to throw her off the Golden Gate Bridge.

According to court documents obtained by SFAppeal the incident occurred after Mayer and Kelli Ann Trent — his girlfriend at the time — attended a house party at Mint Plaza. After pregaming with a couple of Red Bull and Vodkas, Mason allegedly made quite a scene at the party — becoming angry with a bartender who served his girlfriend a glass of water, arguing with Trent about a alleged affair with another woman in attendance and admonishing Trent for speaking with his brother-in-law Zach Bogue, whom he reportedly doesn't like.

From there the accounts get even more disturbing. From the affidavit filed by SFPD Inspector Michael Becker, summarized by the Appeal:

The couple returned to Mayer's apartment at the Four Seasons. Once in his bedroom, Mayer locked the door, allegedly threw Trent down, spit in her face, "pull[ed] her hair out and pull[ed] off her eyelashes" before pulling her by her hair and slamming her head into the marble floor of the bedroom, Becker wrote.

With Trent on the floor "in the fetal position," Mayer allegedly punched her eight times and told her "the only way she was going to get out of this was if he drove her to the Golden Gate Bridge and she jumped off,"

The beating only stopped when a friend of the couple arrived and stayed the night at their apartment to "make sure nothing else would happen."

The Appeal has obtained photos of Ms. Trent's extensive injuries, allegedly inflicted by Mayer that night, that left her face swollen, her eye bloodied and her body scratched and bruised.

So far, Mason Mayer has yet to respond to the allegations, either personally or through his attorneys. He has, however, managed to make a name for himself in swanky social circles despite his short time living in San Francisco, popping up in the society pages at events like 2010's Manus Salzman Valentine's ball and most recently the Midwinter Gala at the Legion of Honor just three weeks ago. We expect he'll be maintaining a lower profile, now that his mugshot is plastered on the Internet.