Sarah Hammond, the chief crown prosecutor for CPS Mersey-Cheshire, said: "The investigation is at an early stage.
"Prosecutors and police are continuing to work at pace to review a huge volume of evidence.
"This includes multiple pieces of video footage and numerous witness statements.
"It is important to ensure every victim gets the justice they deserve."
Jenny Sims, assistant chief constable of Merseyside Police, added: "I fully understand how this incident has left us all shocked and saddened, and I know many will continue to have concerns and questions.
"Our detectives are working tirelessly, with diligence and professionalism, to seek the answer to all of those questions. When we are able to, we will provide further information."