Bodybuilder Richard King and Patrick Allen filed a claim stating they were strangers who had been involved in a serious car crash.
But when Allen asked for money from Direct Line, investigators began digging on Facebook and found a picture of Allen at King's wedding.
They now say the photograph in which the two men are wearing matching tartan proves the pair knew each other all along.
King and Allen attended the same gym and had each other's mobile numbers, a court was told.
Police are investigating whether the crash which is said to have taken place four months before the wedding ever took place.
Earlier this month, the case was thrown out of court after the judge ruled in Direct Line's favour.
A spokesman said: 'The judgment should serve as a stark warning to those who seek to commit insurance fraud.'
King, 47, from Carnoustie, had claimed he pulled out of a junction near Carnoustie, Angus, in his Nissan without being able to see properly in fog and crashed into the side of Allen's Honda.
Both agreed the fault lay with King and Allen, 35, launched a claim with Direct Line worth £25,544.
But assessors became suspicious after examining the damage to the cars.
The firm's team then found the wedding photographs and refused to pay.
Earlier this month, Sheriff Pino Di Emidio, sitting at Forfar Sheriff Court, said there might not have even been a crash.
He said: 'There was good reason in this case to think the alleged accident may have been fabricated.'