Arsonists are suspected of having torched the remains of the former Immaculate Conception College in the Top of the Hill area of the Waterside in the early hours of Wednesday, July 6.
Fire crews were tasked to the old St Brecan’s site at approximately 5am.
The local fire service had to deploy its multistorey fire appliance in the course of containing the blaze due to concerns over the presence of asbestos amid the burning material.
Earlier this year it was revealed the fire service was unable to crew its multistorey engine at Northland Road on a 24 hour basis.
The Northern Ireland Assembly was told in January that firefighters tackling the towering inferno at the Mandarin Palace last year had to go back to the station to get it, making the critical journey to and from the devastating fire, twice.