A woman was taken to taken to hospital after a bin was deliberately set on fire in a close in flats in Renfrewshire.
The incident happened in Thrushcraig Crescent in Paisley at about 21:05 on Friday.
The blaze caused extensive damage to the close.
Police Scotland said a 40-year-old woman was taken to the Royal Alexandra Hospital for assessment. She was later released.
Det Con Jane Perratt, Paisley CID, said: "It is vital that we catch the person or persons responsible for this stupid and cowardly act as they may do something like this again resulting in serious injuries or even fatalities.
"I urge anyone who has any information that could assist our inquiry to get in touch with police immediately.
"I am especially keen to speak to a group of five males and females that were heard in the street just prior to the fire being discovered in the close."