The account of these Galileans being killed by Pilate is not recorded in scripture. However, it was reported to Jesus by those in this account. The Jews of Galilee being killed in the place of sacrifices would have been a terrible occurrence to the Jewish nation. Jesus said, “Do you suppose that these Galileans were worse sinners than other Galileans?” Of course all have sinned (Romans 3:23), but not one sinner is worse than the other.
Repentance was the only way for them to escape perishing in a like manner. It is know that later on the Jewish nation would be overrun by the Romans. This is the like manner in which Jesus was speaking. A violent physical death awaited them and the only way to avoid it was repentance. The concept is the same with “those eighteen on whom the tower in Siloam fell and killed them.” These were not worse sinners than any others. But, “unless you repent you will all likewise perish.” All sin earns the same punishment. Whether it be a lie, or murder, “the wages of sin is death” (Romans 6:23).