The Romans are technically the group of people responsible for killing Jesus, as they performed the actual crucifixion. However, many believe that the religious leaders of Israel are responsible, as they demanded that the Romans carry out his death. These leaders felt Jesus' work threatened their positions in society.
Pontius Pilate is the Roman governor that sentenced Jesus to his death on the cross. Roman soldiers drove the nails into his feet and his hands. Two other individuals were crucified at the same time as Jesus. Jesus was buried in a tomb and rose three days later. This resurrection led to the celebration of Easter.