HELENA, Mont. -

Investigators have not yet come up with a cause for a highway collision between a fire engine and a pickup truck last month that killed all six people in the vehicles.
    
Montana Highway Patrol Capt. Gary Becker said in a statement Monday that investigators and crash re-constructionists will be given as much time as necessary to reach an accurate conclusion.
    
The crash happened June 19 on U.S. Highway 12 about 10 miles east of Helena.
    
Three Forks Fire Chief Todd Rummel was headed east when his fire engine collided with a pickup truck headed in the opposite direction.
    
There were no survivors.
    
The occupants of the pickup truck were 29-year-old Matthew Boegli, 30 year old Crystal Ross and their three young children.