King Clovis was a liar and secretive person. He would send a letter to him, saying now is the time to overthrow his father by disposing of him and becoming king himself. He promised his alliance to the yet-to-be king despite his true intentions
With Clovis' alliance and words still fresh in his mind, the son acted out the plan, killing his father and taking the crown from him
He was manipulated by Clovis, his greed for power and money being targeted in Clovis' words.
Still trusting the man, the son sent a letter back to tell Clovis what he had done and was ready to finalize their alliance. As a reply, Clovis said he would send some of his men to retrieve the treasure the son had offered him.
After he sent the letter, he told his men to meet the son at the castle to 'retrieve' the gold from the prince, only to kill him and send word to Clovis. When the prince's back was turned, the men killed him
After he had heard of the son's death, Clovis quickly rushed over , comforting the people and with his well spoken words, claimed that he should be king as the late Sigibert's kinsmen, and took over the throne as the King of the Franks