According to the information provided, Prime Minister Lin had already seen through everything in Joy of Life2. He had already come to a conclusion about Lin Gong's death. He firmly believed that Fan Xian was the most suspicious true murderer. This matter had something to do with him. Thus, Prime Minister Lin suspected Fan Xian of being his son's murderer from the beginning of the play. In the later parts of the story, Minister Lin tested Fan Xian to see if there were any aces by his side and tested him many times to confirm his judgment. In the end, Minister Lin determined that Fan Xian was the real murderer of Lin Gong.

Prime Minister Lin knew that Lin Gong was the mastermind behind the Niulan Street assassination. In Joy of Life episode 19, Prime Minister Lin told Fan Xian that Lin Gong was the mastermind behind the Niulan Street assassination and tested Fan Xian's attitude toward the Lin family. Fan Xian pretended not to know about this and didn't understand why Lin Gong wanted to kill him, but Minister Lin felt that Fan Xian's reaction didn't seem fake, so he let down his guard. Minister Lin hoped that Fan Xian and Lin Wan 'er would get married as soon as possible and that in the future, the Lin family's business and connections would be handed over to him. Therefore, according to the information provided, Prime Minister Lin knew that Lin Gong was the mastermind behind the Niulan Street assassination.
Prime Minister Lin found out the truth about Lin Gong in the 19th episode of the TV series Celebrating Years. In this episode, the Crown Prince and Minister Lin summoned Fan Xian immediately because of Lin Gong's death. Fan Xian was in a dilemma because of this. Fortunately, the Imperial Army had arrived and delivered the Qing Emperor's orders, asking Fan Xian to enter the Palace for an audience. At this moment, it was Hou Gong…
In the end, Prime Minister Lin knew that Fan Xian had killed Lin Gong. In episode 19 of Joy of Life, Prime Minister Lin told Fan Xian that Lin Gong was the mastermind behind the Niulan Street assassination and tested Fan Xian's attitude toward the Lin family. Fan Xian pretended not to know about this and didn't understand why Lin Gong wanted to kill him, but Minister Lin felt that Fan Xian's reaction was not fake. Thus, Prime Minister Lin finally knew that Fan Xian had killed Lin Gong.
Prime Minister Lin learned the truth about Lin Gong in the 19th episode of the TV series Joy of Life. He directly told Fan Xian that Lin Gong was the mastermind behind the Niulan Street assassination and tested Fan Xian's attitude toward the Lin family. Fan Xian pretended not to know about this and didn't understand why Lin Gong wanted to kill him, but Minister Lin felt that Fan Xian's reaction was not fake. As a result, Minister Lin later learned that Fan Xian had killed Lin Gong.
Prime Minister Lin learned the truth about Lin Gong in the 19th episode of the TV series Joy of Life. In this episode, Prime Minister Lin directly told Fan Xian that Lin Gong was the mastermind behind the Niulan Street assassination and tested Fan Xian's attitude toward the Lin family. Fan Xian pretended not to know about this and didn't understand why Lin Gong wanted to kill him, but Minister Lin felt that Fan Xian's reaction was not fake. Thus, Minister Lin later learned that Fan Xian had killed Lin Gong.
Prime Minister Lin found out the truth about Lin Gong in the 19th episode of the TV series Celebrating Years. In this episode, the Crown Prince and Minister Lin summoned Fan Xian immediately because of Lin Gong's death. Fan Xian was in a dilemma because of this. Fortunately, the Imperial Army had arrived and delivered the Qing Emperor's orders, asking Fan Xian to enter the Palace for an audience. Eunuch Hou was leading Fan Xian into the Palace. Eunuch Hou was also the mysterious carriage driver who had taken Fan Xian to the Temple. Therefore, it can be inferred that Prime Minister Lin learned the truth about Lin Gong in episode 19.
In Joy of Life, Prime Minister Lin doubted the truth of Lin Gong's death, but there was no clear evidence that he knew exactly how Lin Gong died. His suspicions were mainly based on Fan Xian's friendship with Teng Zijing and the fact that Lin Gong had killed Teng Zijing. In Joy of Life2, Prime Minister Lin knew the truth of Lin Gong's death, but he did not specify when he knew the cause of Lin Gong's death.
Prime Minister Lin learned the truth about Lin Gong in the 19th episode of the TV series Joy of Life.
Prime Minister Lin learned the truth about Lin Gong in the 19th episode of the TV series Joy of Life.
In the 19th episode of the TV series Joy of Life, Prime Minister Lin learned that Lin Gong was the mastermind behind the Niulan Street assassination.