No-one will be charged over alleged sexual abuse at a Worcestershire nursery.
West Mercia Police said its year-long investigation into Bright Eyes nursery in Droitwich had now ended.
A man arrested last May on suspicion of sexually assaulting a child at the site has been released without charge.
Police said the age of witnesses and alleged victims had made their investigation "extremely challenging".
Six men were originally arrested in May after a mother reported her child had been assaulted.
Properties, including the nursery chain's three branches in Droitwich, Redditch and Bromsgrove, were searched.
In July, police received a complaint a second child had been incited to engage in sexual activity,
Five of the six men were later released without charge.
West Mercia Police said it would take no further action against the sixth man, who had remained on police bail, in relation to the allegations of sexual abuse.
Det Ch Insp Damian Barratt said officers had identified "a clear lack of control within the nursery setting", including "unauthorised people having access to the childcare environment".
Sarah Hammond, of the Crown Prosecution Service, said it had decided there was "insufficient evidence to provide a realistic prospect of conviction".
Ms Hammond said the CPS had sent an explanation to the families involved and offered face-to-face meetings if they wished to discuss the matter further.
The nursery chain has since closed after its directors withdrew their Ofsted registration.