Police are appealing for witnesses and information following a fire at Redding House in Tolpits Lane, Watford at 8.45am.
Hertfordshire Fire and Rescue were on the scene and quickly dealt with the blaze. Around 20 people were evacuated from the flats and were taken to a place of safety.
Ambulance were on the scene and one woman was taken to hospital with injuries not thought to be life threatening. Otherwise, no other injuries were sustained.
Senior Investigating officer Detective Inspector Matt Phillips, said: “We are currently treating the fire as suspicious and are appealing for anyone who was in the area at around 8.30am to 8.40am, and saw anyone acting suspiciously, to please get in touch.
“Two men were seen leaving the scene in a blue Astra (an older shaped model). Did you see these men or the car? If so please give us a call. Any information you provide, no matter how small could help us with our enquiries and find the people responsible for this incident.”
Alternatively, you can contact the independent crime-fighting charity Crimestoppers anonymously on 0800 555 111 or through their Anonymous Online Form at www.crimestoppers-uk.org. No personal details are taken, information cannot be traced or recorded and you will never need to go to court.