There are no existing eyewitness or contemporary secular accounts of Jesus that I am aware of.
The strongest evidence for Jesus's existence is the Gospels. It seems implausible to me that those authors would make up a story about somebody who didn't even exist. There probably was a man named Jesus and he was probably crucified.
Jesus's last words were supposedly "my God my God why have you forsaken me" according to Mark (the earliest gospel). This makes absolutely no sense unless Jesus was NOT God. It would be like me saying "bshole bshole why have you forsaken me". It is also indicative of a person who was perhaps surprised and anguished by his predicament, not an entity that was fulfilling a purpose he had planned for before the creation of the universe....... sacrificing himself (well sorta, 3 days as a spirit in the underworld is hardly a "sacrifice") to himself so that he could create a belief test (as a barrier to heaven and an entrance to hell) which the vast majority of civilization would fail..... this in spite of the fact that we now know SCIENTIFICALLY that belief is not a choice but simple brain physics that God put into our heads.
I find it very troubling that Jesus's last words were then changed by later authors in Luke and John to indicate something completely different, first "into thy hands I commend my spirit" and finally "it is finished". This is pretty direct evidence of a theology in development.