The first minister has warned that police will pursue anyone who spreads misinformation suggesting asylum seekers were due to use flats in Glasgow which were later set on fire.
The blaze broke out on Sunday at a building in Stonyhurst Street, Possilpark, which had been targeted by anti-immigration protests in recent months.
Some £3m of public money had been put towards renovating the tenement - which has been derelict for 20 years - to create affordable homes.
Speculation has spread online that the fire was started deliberately over concerns the building would be used to house asylum seekers, a claim which has been rejected by operator NG Homes.
John Swinney said the incident was "absolutely deplorable" and warned that anyone celebrating the blaze would also be pursued by police.
Det Insp Neil Martin said the fire started on the fourth floor at about 16:50 and urged anyone who saw anything suspicious to get in touch.
Glasgow MSP Paul Sweeney claimed there was evidence the blaze was started deliberately following online "disinformation".
During First Minister's Questions from backbench MSPs, he asked the first minister if he would assure parliament that anyone spreading misinformation about the flats or celebrating the fire would be investigated.
Swinney replied: "Those who are responsible for the action will be pursued, those who were circulating information to incite this behaviour will be pursued, and those who have been responsible for celebrating such behaviour will also be pursued by Police Scotland."
Prior to the fire, two protests had been held outside the building - one in July and another in early August - after it was claimed online that the flats, once refurbished, would be used to house asylum seekers.
Since the blaze, images of the building with flames shooting from the roof have been circulated by right wing social media accounts describing the tenement building as "migrant apartments".
Swinney added: "I want to make it clear to parliament today, that when we are wrestling with housing challenges in our country, for people to go around wasting public money by setting flats on fire that are being renovated is an absolute disgrace.
"It undermines the efforts to improve the quality of life by providing good housing for members of the public in Scotland.
"So everyone who is involved in this inciting of racial tension, to stir this up, to lead to the destruction of good accommodation, is a disgrace and they'll be pursued by Police Scotland."
NG Homes said it was in the process of refurbishing and upgrading a number of buildings on the street "to provide much-needed affordable homes".
A spokesperson added: "These properties will be allocated in line with our allocations policy and Scottish housing legislation from our existing housing list.
"As a registered social landlord, we do not allocate housing to people who are not legally eligible for it."
Glasgow City Council said that, working with NG Homes, more than 3,500 empty homes had been brought back to "productive use" in recent years.
It said grant funding for refurbishment came through the Affordable Housing Supply Programme.
The council's housing convener Ruairi Kelly previously told BBC Scotland News it was "really difficult" to counteract misinformation, like the suggestion the building would be used to house asylum seekers, because "a lot of people are in a position where they want to believe the worst".
He stressed that the new housing was intended to be used by people in the community.