Rob Reiner and his son Nick were involved in a heated altercation at Conan O'Brien's Christmas party on Saturday night, December 13 - just hours before the famous film director and his wife Michele Singer Reiner, were found murdered inside of their Los Angeles home.

The Princess Bride director got into a "very loud argument" at the A-list bash, with their amplified conversation being vocalized enough for other guests to hear, family sources revealed to TMZ shortly after Nick was arrested in connection with his parents' brutal killings.



MORE ON:Rob Reiner News, Updates, and Gossip from OK! MagazineRob Reiner's Eerie Remark Resurfaces: Actor Spoke About Loving 'All' of His Kids, 'Even the Bad Ones,' Months Before Son Nick Stabbed Him to DeathInside Rob and Michele Reiner's Lavish $4.75 Million L.A. Mansion Where They Were Tragically Killed: Watch Rob Reiner and Wife Michele Found Dead in L.A. Home With Knife WoundsWant OK! each day? Sign up here!According to the insiders, Rob and Michele left O'Brien's gathering shortly after the explosive argument between the dad-of-four and his son, though it is unclear if Nick left at the same time or on his own accord.

The family sources spilled that Michele had grown tired of dealing with Nick's mental health issues in the months leading up to her death and complained to friends about her son's addiction struggles."We've tried everything," Michele reportedly told friends after recently hitting her breaking point with Nick.

More to come...