Police in Midlothian are investigating a deliberate fire-raising in a block of flats in Dalkeith.
The fire broke out around 9pm on Friday, within the common stair of the block of flats in Chester Square, which is in the Mayfield area.
No one was injured as a result of the blaze, however all of the residents have been re-housed because of smoke damage.
The damage is estimated in the region of £15,000.
A police spokesman said: “This was a deliberate act which could have had serious consequences, and we are appealing for any information that can assist our inquiries.
“Anyone who was in the area of Chester Square around 9pm on Friday, who noticed anyone acting suspiciously in the area, should contact police immediately.
“Anyone else who has any information that can help our inquiries should also get in touch.”
Anyone with any information should contact Lothian and Borders Police on 0131 311 3131, or Crimestoppers in confidence and complete anonymity on 0800 555 111.