That is Paul's assertion in 1 Cor 15:6-8. Paul claims that there were people still alive who saw Jesus. Of course, the explicit mention in v. 6 is to people who "saw" Jesus after he supposedly rose from the dead.
There is also this: until 6 CE, Judea was a client kingdom of Rome, not a directly ruled province. While Judea was a client kingdom, they had the authority to execute criminals: it was only after Judea became a province that crucifixion was used. (Culturally, because of their religious rules, the Jews avoided hanging, impalement, crucifixion, or similar methods of execution. The Herodians were not themselves ethnically Jewish, but according to Josephus they pretty much ruled with sensitivity to Jewish religious customs.)
Now, by the time the Gospels were written (GoMark was probably written within the first three to five years after the destruction of Jerusalem), few if any eyewitnesses survived. By tradition, neither Mark nor Luke were eyewitnesses (which is utterly unimportant if the Gospels attributed to them are misattributed, a question where there is insufficient evidence to establish or refute). So no, the Bible contains no eyewitness accounts. There _may_ be some filtered second-hand accounts in GoMark if the traditional attribution is correct, but if so, Mark added material to suit his didactic purposes, and he flubbed some of the details (such as the geography around Galilee).
AH, as you can see, I can blather on for several paragraphs on this topic.