Nick Reiner entered a not guilty plea to two counts of first-degree murder after being accused of fatally stabbing his parents, Rob Reiner and Michele Singer Reiner, late last year, but a legal expert said his defense team will still likely have an uphill battle if the case goes to trial. "The fact that Nick got into an argument with the victims a day before the murders at Conan O'Brien's Christmas party is fatal to any real defense in the case," former federal prosecutor Neama Rahmani, president of Los Angeles-based West Coast Trial Lawyers, told Us Weekly exclusively after the defendant's co...