Rob Reiner got into heated argument with son Nick Reiner before his death

Rob Reiner and his son Nick Reiner got into a fiery argument at Conan O’Brien’s Christmas party om Saturday night.

As multiple sources at the party told PEOPLE, the late director and Nick got involved in a “big fight” at the holiday celebration just hours before Rob and his wife Michele Singer were found dead on Sunday.

TMZ first reported on Monday that the 78-year-old filmmaker and his 32-year-old son had a “very loud argument” at the party hosted by Conan O’Brien, while two sources later confirmed the incident to PEOPLE.

One source described Nick’s behaviour at the party, telling the magazine, “Nick was freaking everyone out, acting crazy, kept asking people if they were famous.”

According to TMZ, Rob and his 68-year-old wife left the party following the argument. 

The couple were later discovered slain in their Los Angeles home on Sunday, December 14. Sources previously told PEOPLE that their daughter Romy had found them.

The Los Angeles Fire Department responded to a call at the Reiner residence around 3:30 p.m. local time to provide medical assistance. Upon arrival, first responders found Rob and Michele.

Nick Reiner was later arrested and charged with murder and is currently being held without bail.

For the unversed, Rob Reiner and Michele Singer met while he was directing When Harry Met Sally… and were married in 1989. They had three children together: Jake, Nick and Romy.