Two fires started yards apart in Kilmarnock town centre are being treated as deliberate after fire crews were called out to tackle the flames.
Emergency services responded to incidents on King Street and Sandbed Lane within the space of three hours on the evening of Friday, May 20.
The Scottish Fire and Rescue Service (SFRS) extinguished both incidents after the alarm was initially raised on the busy shopping thoroughfare shortly after 7.55pm.
Firefighters left the scene, but were forced to return at 10.55pm to a property on Sandbed Lane, less than 30 yards away, when the building was reported to be ablaze.
No one was understood to be hurt in either incident, but police now believe both were ignited “wilfully”.
Additional officers are set to patrol the area in the coming days to “provide reassurance” to locals.
Detective sergeant Sarah Holland, of Kilmarnock CID, has asked any motorists who may have captured the fires on dashboard-mounted cameras to come forward and share it with investigators.
DS Holland added: “Our enquiries are ongoing and anyone who may have seen anything suspicious on the evening of Friday, May 20, is urged to get in touch.
“I would also ask any motorists who were in the area to check their footage in case it holds any information that may assist us.
“Additional patrols have been put in place to provide reassurance and anyone with any concerns is encouraged to speak directly with an officer.
“Anyone with information is asked to contact Police Scotland via 101 quoting reference number 3875 and 4207 of Friday, May 20, 2022 or by calling Crimestoppers anonymously on 0800 555 111.”