I'm at work though, and would need to muster sources and hours to dedicate to a proper treatment of this question.

Let's start by losing the word 'bible' when we talk about this and focus on the books of the new testament purported to

discuss the life of jesus. None of the rest of the bible is alleged to be an eye witness account.

I'm talking about Mathew, Mark, and Luke, specifically. I'm not sure anyone could seriously argue John was an eyewitness account.

All these gospels are pseudepigraphic - they are written in the names of famous dead characters by unknown authors.

Of these Mark is the oldest and is the one used as a reference by all the others. In fact, Mathew lifts great hunks of Mark, or re-writes them

with odd little variations on the characters. In none of the gospels is there evidence that they were based on reliable historical sources, whatever

christians might say about them. There are other oddities. While most the gospels use Mark,  Luke and Matthew seem unaware of each other

and Luke seems to have had no idea of John. It's considered John was written at least a hundred years or more after the death of John the Apostle

and there is a case that this John was based on Messiah Theudas who was crucified in 44CE and his disciples murdered. John only touches on Mark and

ignores matthew and luke completely. John was not intended to be historical and like the others contains no reliable historical sources.

Mark was written some time after the destruction of the temple in jerusalem because it mentions the event and christians argue Mark wrote

his gospel about 75CE when he was an elderly man. Trouble is, linguists argue the style of Mark indicates it was originally written in Latin and

translated into Greek later. The oldest known greek translation contains charaterisations distinctive of latin/greek translation.

Scholars say it's likely Mark was written in Rome by a Roman convert. Apparently the current Mark dates from about 150 CE and Clement of Alexandria

who died around 215CE complains bitterly about early versions of this gospel that were floating around in his lifetime. It's likely Mark was repeatedly edited during the first centuries of the early church.

There's a lot more to know about the early christian writings and none of it helps their cause. The early church's writings and backbiting are a fascinating study as the power bases sought to seize ownership

of the powerful new cult. Particularly bitter was the contest between christianity and the established cult of mithraism from which christianity seems to have adopted much including the son of god, virgin birth,

descent into hell by god figure to atone for sins of the world, the concept of eternal life for believers, blood sacrifice and lots more.

The fabrication of St Peter's trip to Rome came long after his death to give the church in Rome a Saint/demigod of its own.

Paul's alleged death in Rome under Nero is another example of the Roman church's ownership of christian pre-history. The early church historian Eusebius was instrumental in much of this fabrication

and his letters encourage fabrication as a way to strengthen the Church's case. For example Eusebius wrote to a friend along the lines of - "As an additional source, let us use Josephus the Jew" - the trouble

with this being that Josephus was by then hundreds of years dead - Eusebius became bishop of palestine around 314. Interestingly, a copy of Josephus with a bald, out of context mention of Jesus was

subsequently found in Eusebius' library and is oft quoted by Christians as additional historical proof, despite the fact earlier Jewish copies don't include the insertion.

The relevant paragraph starts off something like: "About that time there lived in Judea a man, if it be right to call him a man, for he was the christ".  This is not the sort of thing Josephus or any other practising jew

would have written and is clearly penned by a christian.

A common christian argument in relation to the gospels is that despite their individual frailty they must be considered a coverage as comprehensive as any other of the time and thus represent a weight of

evidence that pushes the argument in the direction of the existence of jesus and the veracity of the crucifixion story but these are vacuous claims. The fact remains

these 'eyewitness' accounts to events in far away Judea were penned at least 75 and probably more than 150 years after the events they claim to describe, in a foreign language in another country by authors unknown. 

I know this is not a clean answer to your question but the point is that gospels are highly questionable, contain no actual proof, no eyewitness accounts and blatently weave OT references and

prophecies into their fabric, along with glaring errors based on earlier mistranslations of jewish writings.

They should be taken with a commodious shaker of slat.