The son of man (Jesus) wasn't so for the Son of God came through Mary by God through "The Holy Spirit" (the Triune) consisting of three in one (used especially with reference to the (Holy Trinity).created by God.
The Holy Spirit has always been part of God and through the Holy Spirit and Gods Will, Jesus was created using Joseph as a surrogate father, hence Son of Man but in reality He was the "Son of God."
When Jesus was put to death He was resurrected and returned to his Father, God.
The question of whom killed Jesus has not been resolved as yet but God Almighty knows.