A CSI-style squad has been set up to investigate all suspicious fires in Scotland.
Fireraising crime scenes will be carefully preserved so that the specially trained team can extract every possible shred of evidence and track down the culprits.
Forensic investigators say even a badly-burned crime scene can give away residues of blood, petrol and fingerprints if it is treated properly.
The agreement between the police and fire services comes after three members of the Sharkey family were killed in 2011 when their house in Helensburgh, Argyll and Bute, was set on fire, a crime which saw two men convicted of murder this year.
Fire chiefs say they deal with 20,000 deliberately set fires each year.
There were 558 cases of wilful fire-raising in Glasgow alone in 2011/12.
A spokeswoman for the Scottish Fire and Rescue Service said: “Rather than us putting the fire out and then the police coming to investigate, we will all be engaged at the scene of incidents and we now have three national specialist units to investigate wilful fire ?raising.”
Tom Nelson, director of Scottish Police Authority Forensic Services said new training would ensure as much of the crime scene as possible would be preserved.
He said: “When the fire service goes in its priority is to put out the fire and make sure people get out safely.
“But what this agreement allows us to do is work on joint training and a joint approach to ensure we have material preserved at the crime scene for evidence.
“As scientists we go in to identify the seat – or origin – of the fire, take samples of debris and look for residues of accelerants such as petrol.”
He continued: “The most important thing ?for us is for the scene to be as intact as possible. It could be, in the case of a murder, there are ?the remains of a weapon with blood still on it.
“We could still find fingerprints after afire. There ?is a lot of potential evidence.
“As forensic science advances we can get meaningful information from smaller and smaller samples.
“However, protecting the integrity of the crime scene is vital in giving us a complete understanding of how the fire started and who was responsible. ”
The new scheme comes after three members of the sharkey family were murdered when their home in Helensburgh, Argyll and Bute, was set on fire in July 2011.
Thomas Sharkey, 55, his son Thomas, 21 and eight-year-old daughter Bridget were killed.
Scott Snowden, 38, and Robert Jennings, 50, were convicted of murdering them in July this year.
Police launched an internal review into how they investigate in Helensburgh before the Sharkey murders, with 56 reports of wilful fire raising in the area between 2010 and 2012.
Chief fire officer Alasdair Hay said: “Those responsible for deliberately setting fires should note how determined we are to prevent them endangering people and damaging property.
“Fire is incredibly unpredictable and is completely beyond the control of those who start it. People who set fires deliberately are endangering lives by their reckless, criminal actions.
“Scotland’s firefighters attend about 20,000 deliberately set fires each year, which shows the importance of our expert officers working to identify the causes and supporting the police with evidence to track down those responsible.”
Chief Constable Sir Stephen House said: “This protocol will help shape a modern and effective response to wilful fireraising that can be held up as an example of excellent joint working.”