Yes, lynch mobs or similar groups would frequently kill larger numbers of people without being charged. Some good examples of this include the "Red Summer" of 1919, the destruction of Greenwood, Oklahoma, and the Rosewood Massacre.

The violence would often occur after a black man was accused of assaulting a white woman. Sometimes the man couldn't be found and the mob would attack the black community anyway, sometimes the victim would be lynched and the mob would continue on to attack the community. If the black community resisted or tried to organize an armed defence, a rumor would then spread of a "negro uprising" that lead to even more violence.

The perpetrators of the attack rarely faced any consequences. In several cases, the police had even instigated the violence or conflict. Even if the police were trying to prevent or stop the violence, there was very little chance of being prosecuted. Far from worrying about hiding their actions, whites would often keep souvenirs like pieces of the victim's skin or fragment of a rope used for hanging.