A 40-year-old woman has been seriously injured after the home she shares with her nine-year-old daughter was deliberately set on fire.
Police said they believe an accelerant was thrown through the window of the Wellington Street property in Greenock at about 23:00 on Wednesday.
They are investigating whether a small white car, seen speeding off near the property, was involved in the incident.
The nine-year-old child was uninjured in the attack.
The woman was taken to Glasgow Royal Infirmary where she remains in a stable condition.
The fire, which was extinguished by the Scottish Fire and Rescue service, resulted in the block being evacuated and substantial damage to the building.
Detectives say a small white vehicle was in the area at the time of the incident and was seen to drive off "at speed" in the direction of the junction of Wellington Street and Duncan Street.
About 10 minutes later, a white Suzuki Splash, with registration number GK14 FZE, was driven into Skye Street in Greenock at speed.
Police say three men got out of the car and ran off down Skye Street and into Rankine Street. They are all described as being in their late teens and of skinny builds.
The driver was wearing a black scarf covering the lower part of his face and a black zipped hooded top.
Both the front passenger are described as wearing something over their heads with grey zipped tops with the hoods up.
The Suzuki Splash was found burnt-out in Skye Street in the early hours of Thursday. It has since emerged that the car was reported stolen from Denholm Terrace in Greenock in the early hours of 16 September.
Det Insp David Wagstaff said: "This was a sickening, unprovoked attack which targeted a woman and her child whilst they were in their home.
"There will be those within the community that will know who is responsible and I would encourage you to please do the right thing and come forward with information."
Officers are urging anyone who saw the white vehicle or have CCTV or dashcam footage to come forward
Det Insp Wagstaff added: "We are investigating whether the Suzuki Splash, parked and later burnt out in Skye Street, is involved in the fire on Wellington Street.
"If anyone has any information around the initial theft of the Suzuki Splash around 4.30am on Wednesday, 16 September, or has information as to where it was before it was parked on Skye Street just after 11pm on Wednesday, 16 September, I would urge you to please get in touch."
Additional police patrols are being carried in the area. Police said there was not thought to be any risk to the wider public.