By far the most famous fraud in all of Evolutionist history is Ernst Haeckle's fake embryo drawings. In 1868, in an attempt to prove Evolution, Haeckle faked several drawings of the embryos of various animals, and with the catchy slogan "ontogeny recapitulates phylogeny", he pushed the idea that as an animal develops in the womb or egg, it resembles its evolutionary ancestors.
Even during his own lifetime, Haeckle's works were brought into question. Even the biologists of his day, with their limited technology, were able to pick apart his fraudulent works like vultures on a corpse, eventually forcing Haeckle to confess "What difficulties this task encounters, and how easily the draughts-man may blunder in it, the embryologist alone can judge." (1) This confession is weak and spineless, as he, himself, was the draughts-man, and "blundering in it" is a bit of an understatement.
But even though the fraud was discovered during Haeckle's life, it persisted long after his death, right up until 1997, when Dr Michael K. Richardson (an Evolutionist himself) published several photographs of the relevant embryos. When compared to Haeckle's frauds, they were proven to be far more different from the drawings than had previously been believed.
This discovery tore the Evolutionary community in two. While more honest Evolutionists, such as Stephen Jay Gould, appreciated the publications, other Evolutionists, such as Robert John Richards, a professor of history at the University of Chicago, were utterly devastated. Even as late as 2008, he published a paper entitled "Haeckel’s Embryos: Fraud not proven."
Scientific fraud is no joke. This is far from the only example. It's just the most irritatingly stubborn one, and if it had dropped out of circulation as soon as it was discovered, Evolution may not even have taken root in the Western world. But the use of this fraud continues, because it is propping up a bigger fraud. Without such "powerful" evidence as Haeckle's frauds, Evolution would be impossible to maintain, and whereas Christianity explicitly forbids lying, even as one of its most famous 10 commandments, Evolution has no such laws. In fact, it has no laws at all. Thus, not only is lying a strong defence of Evolution, it is consistent with it. It is unlikely that Haeckle's frauds will drop out of circulation until Evolution itself dies as a religion, but however long the fraud survives, a fraud it remains. Evolutionists must therefore consider that they have been lied to rather egregiously.
References
1. Haeckle, Ernst, cited in The Truth about Haeckel’s Confession’, The Bible Investigator and Inquirer, M.L. Hutchinson, March 11, 1911