They put him to death by hanging him on a tree.

Acts 10:34, 37-43
34 Peter proceeded to speak and said: 37 “You know what has happened all over Judea, beginning in Galilee after the baptism that John preached, 38 how God anointed Jesus of Nazareth with the Holy Spirit and power. He went about doing good and healing all those oppressed by the devil, for God was with him. 39 We are witnesses of all that he did both in the country of the Jews and in Jerusalem. They put him to death by hanging him on a tree. 40 This man God raised on the third day and granted that he be visible, 41 not to all the people, but to us, the witnesses chosen by God in advance, who ate and drank with him after he rose from the dead. 42 He commissioned us to preach to the people and testify that he is the one appointed by God as judge of the living and the dead. 43 To him all the prophets bear witness, that everyone who believes in him will receive forgiveness of sins through his name.”

Thank You God. Amen.
Happy Easter everybody! :)