Read: Matthew 27:62-66
and said, “Sir, we remember how that impostor said, while he was still alive, ‘After three days I will rise.’ (Matthew 27:63 ESV)
Once Jesus' body had been entombed a group of religious zealots gathered before Pilate. This was the same group that had had Jesus murdered. The same group that had regularly pitched a fit over Jesus performing miracles on the Sabbath were gathering with Pilate on the Sabbath to get someone to seal the tomb.
They remembered Jesus' own words. They remembered his promise to rise again. And they were so blinded by their religious idiocy that they thought to thwart it, proof that they never actually comprehended what was about to happen.
Pilate granted their wish. The tomb was sealed. Guards were posted. The religious goons were satisfied. No one was going to steal he body of Jesus. No one would make false claims about his resurrection.