India, Dec. 16 -- Nick Reiner, who has been arrested in connection to the murders of Rob Reiner and Michele Singer Reiner, "freaked out" and had a huge blow-up with his parents at Conan O'Brien's Christmas party a day before the murders, a source told the New York Post.

Rob and Michele's bodies were found inside their Brentwood home on Sunday, December 14. Los Angeles police said in a statement that Nick was "responsible" for the deaths, according to CNN.

Nick had a "very loud argument" with Rob and Michele at the party, possibly fueled by him going back on drugs and refusing treatment, the source added. Nick has reportedly been in and out of rehab for his drug addiction.

"They had had an argument at Conan's holiday party, and Rob had ...