In Raimonian culture, it was traditional to hold a death celebration when a person learned that their death may be imminent. Tardol first met Jean-Luc Picard of the USS Stargazer during the death celebration of the Primarch at that time. In 2365 Picard was again summoned to Raimon to attend the death celecration of the current Primarch.
When Tardol first saw Picard, he was surprised that Picard had dared to come since assumed that Picard had been told that he wasn't welcome. In fact, the Primarch had wanted to tell Picard that he was going to terminate a mining contract that Raimon had with the Federation, but he was murdered before he had a chance to do so. Both Picard and Tardol were at the scene of the crime and were initially blamed for the murder.
When Picard refuses to plead diplomatic immunity, Tardol invoked a right to trial by combat to determine guilt or innocence. Hoping to find evidence of Tardol's guilt but unable to find any, Counselor Troi was eventually able to deduce that Lutina Gaspadral, the Primarch's daughter was actually guilty. While Riker stood in as Picard's champion to battle Tardol, Picard confronted Lutina and got her to confess to the crime. As it turned out, Lutina had lured Tardol to the crime scene hoping that he would be blamed for the murder while Picard's attendance was simply an unfortunate coincidence.
Unknown to Lutina, the prosecutor of the case was hidden nearby and could hear what was going on. He and Picard then went to the arena and interrupted the battle just in time to prevent Tardol from killing Riker in combat. (TNG comics: "Return to Raimon", "Murder, Most Foul")