Which king tried to kill baby Jesus?

Answer: Herod

King Herod was going to search for the child to kill Him.

“When the Magi had gone, an angel of the Lord appeared to Joseph in a dream. “Get up!” he said. “Take the Child and His mother and flee to Egypt. Stay there until I tell you, for Herod is going to search for the Child to kill Him.””— Matthew 2:13 (BSB)