David and Susan Thompson, who are in the process of moving from San Diego to Erie, Penn., were driving east on I-70 near exit 41, when their 1988 Fleetwood Bounder began smoking heavily.
The RV caught fire shortly before the couple pulled over to the side of the road at about 4:41 p.m. on the I-70 overpass across U.S. 231, Indiana State Police Trooper William Patterson said.
Three good Samaritans, Eric and Amanda Browning, of Indianapolis and Brian Weitz, an Indiana National Guardsman from Morrisville, Ind., stopped and helped the couple pull as many of their pets -- three cats, three dogs and two birds -- as they could from the camper.
Eric Browning said David Thompson tried to go back for the three remaining cats in the vehicle, but it was fully engulfed with a fire fed by strong winds and too dangerous to approach.
Neither David nor Susan Thompson were hurt in the blaze, though David's anguish was visible as Cloverdale Township Volunteer Firefighters pulled the charred remains of his cats from the wreckage and handed them to him.
Most of the couple's belongings are still in California, so fortunately all the lost otherwise were a few changes of clothes.
Susan Thomson said she believes the fire was started by burning oil on the transmission left from a repair stopover in Missouri Tuesday.
Police forced all eastbound vehicles to get off the highway at exit 41 to avoid the fire. This caused traffic to slow to a crawl for about five miles west of town.