Because the children are in shock and need to provide their story of the incident to the police first before they speak to any other person
Explanation:
The children have to speak to the police first because they were there when the incident occurred and hence have a fresh memory of everything that occurred hence it would be best if they speak to the police first because they would say the truth. On the other hand, the journalists might ask them questions which would make them confuse or better still influence them to report things which did not really happen during the incident