Deaths of Jesus’ disciples

Hello. What proof do we have the disciples were killed for their faith?

The Bible provides information about the martyrdom of the apostle James (Acts 12:2). Beyond that, historians and other writers offer accounts of the deaths of Jesus’ disciples. It is thought that all the disciples, with the exception of John, were put to death for their faith in Jesus Christ.

Prior to their deaths, Judas Iscariot took his own life (Matthew 27:5).