Birmingham City Council said it had received more than 200 reports in relation to its inquiry.
It has appointed former head teacher Ian Kershaw as its chief advisor.
Anonymous claims hard-line Muslims were trying to take over the running of some city schools were made in a letter sent to local authorities last year.
The 25 schools now being looked at include primaries, secondaries and academies.
The 200-plus reports to the council include emails and calls from staff, parents and governors. (+ BBC video) » | Monday, April 14, 2014
