A huge fire at a former school in Midlothian is being treated as suspicious, police have said.
The blaze caused extensive damage to the old Paradykes Primary School in Loanhead on Saturday night.
Emergency services were called to the building at 21:37, where they found it was "well alight".
They were alerted to the possibility a person was trapped inside but it was later confirmed there were no casualties.
Police said they were conducting door-to-door inquiries and checking CCTV as part of their investigation into the blaze.
Insp Neil Mitchell said: "We have information that a number of youths were seen in the area near to the building prior to the fire starting.
"We are appealing for anyone who may have been nearby and saw any youths at the building, or have information relating to the fire, to contact us on 101.
"We're also keen to hear from anyone who may have their own CCTV system in or around the area of Mayburn Walk to get in touch."
Appliances from Dalkeith, Liberton and Penicuik attended, using pumps and hoses to tackle the flames.
A Scottish Fire and Rescue spokeswoman said: "They fought the fire externally as the building was fully involved."
Crews were still at the scene at 07:00 on Sunday to dampen down the area.