Police say they still do not know what started a fire in Hamilton that killed three people.
Toni Johnston who was 23, Jake Hayes who was 19, and Connor Swetman who was 17 all died at their century-old flat in November.
The villa was engulfed in flames after a party and the fire was initially treated as suspicious.
Police said the case remained unexplained because forensic evidence had not been able to take their investigation forward.
They are still reviewing items taken from the scene to decide if any more tests should be done.
No particular person is being sought by the police in connection with the fire, but the case remains open.