Thieves broke into a nursery in Wellingborough and stole a safe containing cash.
Highfield Nursery School in Finedon Road was broken into at about 8.30pm on Tuesday, December 1.
After searching the building, the thieves broke into a cupboard and stole a safe which had money in it.
They also broke the lock on a second safe, but that was empty.
Witnesses, or anyone who knows anything about this incident can call Northamptonshire Police on 101 or call the independent charity Crimestoppers anonymously on 0800 555111 or use the anonymous online form at www.crimestoppers-uk.org.