Because the New Testament provides the primary historical source for information on the resurrection, many critics during the 19th century attacked the reliability of these biblical documents.
As a reward for their efforts, however, those early Christians were beaten, stoned to death, thrown to the lions, tortured and crucified. Every conceivable method was used to stop them from talking.
If they had connived a scheme, and Christ had not been raised from the dead, where would have been the hardest place on the face of the earth to convince anyone? In Jerusalem.