This question concerning Christ's crucifixion has been brought up before. In the thread "Biblical Contradictions," the following statement was made. "There are contradictory accounts of when Jesus was crucified, depending upon which Gospel you read. Matthew, Mark, and Luke all have him being crucified after passover, while John has him being crucified BEFORE Passover."
I believe you will find the response which I posted to that statement to be of interest in this debate.
"At the time of Christ, there were two timetables in use by the Jews. The Galileans measured each day from sunset to sunset while the Judeans measured from sunrise to sunrise. Therefore all the Galileans, including Jesus and His disciples, would have eaten their Passover meal on what would be by our reckoning Thursday night. The Judeans, on the other hand, would not have eaten their Passover meal until Friday evening. Thus Christ's crucifixion would have taken place after His own Passover meal but just prior to the meal of those who crucified Him.
This explanation is supported by Mark 14:70. In that verse, Peter is told, "Surely thou art one of them: for thou art a Galilaean, and thy speech agreeth thereto." Why would they associate Peter with Christ merely because he was a Galilean? The Galileans had a custom in which they did not work during the day of the Passover. The Judeans, on the other hand, kept the custom of not doing any work after noon on the day of the Passover. Thus any Galilean mingling with a crowd of Judeans on Passover morning would be suspected of being associated with Christ."
I do not, at the moment, have time to discuss the topic to any great detail, but further information can be obtained from the appendix to the book,
The Words and Works of Jesus Christ by J. D. Pentecost.