Birmingham City Council's Cabinet member for Children and Family Services has said allegations relating to extremism in the city's school span from 20 years ago to right up to the present day.
Speaking to ITV News, Cllr Bridget Jones said: "So far the allegations that have come in recently relate to things that are happening present day, as well as things that happened 20 years ago.
"We have got a very wide range here. Each of these allegations, we will look into individually. We hope to build up a full picture as to what has happened. We think some of it will be related to Trojan Horse [investigation], maybe some of it not."
Birmingham Council has published a list of schools which were inspected as a result of an alleged plot to seize control of governing bodies.
Peter Clarke has been appointed oversee investigation into hardline Islamist takeover plot at Birmingham schools.
The number of schools being investigated in an alleged hardline Muslim plot to force out governors and headteachers has now broadened to 25.