You’re right, we don’t know anything except LE has never associated a vehicle to the killer when asking for tips regarding his identity.
Another great mystery of this case IMO is why, between LE and the family, they couldn’t nail down an agreed upon time when the girls were dropped off. Establishing a fairly precise timeline would seem to me to be critical when seeking information. The 1pm drop time has been reported over and over again.
“The girls were dropped off at the trail at 1 p.m.......according to Indiana State Police...”
Mystery surrounds Indiana murder of 2 teen girls: ‘We cannot fail on this case’
“At 1:35, we arrived at the entrance to the bridge, the girls got out of my car, and I never saw them alive again.”
Halfway Across: The Delphi Murders