Three men were hurt in the "targeted attack" in Cardowan, near Glasgow, when vehicles were set alight and a village street left resembling a "war zone".
Detectives now believe an incident an hour earlier, in which men in two other vehicles tried to block in a Ford Transit van, could be connected.
The van was later stolen and used in Sunday's Cardowan attack.
Det Insp David Reilly said: "What we know now is that around 12:30 on Sunday 5 June 2016, a 46-year-old man was driving his silver Transit van on Cumbernauld Road, Riddrie, when two cars, a blue BMW X6 4x4 and a white saloon car, each with three male occupants, tried to block him in.
"He managed to turn his vehicle around and speed off north along Cumbernauld Road over the motorway and towards Gartloch Road in Ruchazie where he lost the two other cars who had been pursuing him."
The van was later stolen from a street in Ruchazie.
The 46-year-old was one of the three men later attacked in Cardowan when his van was used to ram another Ford Transit van before its occupants were assaulted.
Det Inp Reilly added: "I am pretty sure, especially at this time of day and the fact that the van, which had ladders on the roof, crossed over on to the wrong side of Cumbernauld Road to get away, that someone would have either have had to swerve to avoid the van or would have at least seen the incident happen.
"If you did, then please contact police.
"The BMW and its owner have since been traced and inquiries are continuing in that regard, however, we still need information about the white saloon car."
Police have said an attack on three men in North Lanarkshire may be linked to an earlier road rage incident.