Paddock suspicions were aroused when Karam spun and brought out a caution just after team-mate Scott Dixon had made his final visit to the pits, but before race leader Juan Pablo Montoya had stopped.

The reshuffle under the caution elevated Dixon and eventual race winner Graham Rahal up to the front, and dropped Montoya into the pack.

However IndyCar’s review of the incident, which included analysis of car data and radio transmissions, failed to unearth definitive proof that the spin was deliberate.

Elsewhere, Dale Coyne Racing and driver Rodolfo Gonzalez were fined $500 each for minor pitstop infractions, while Chevrolet received both a 10-point bonus and an 80-point deduction relating to the 2500-mile minimum lifespan of its engines.

Following the point adjustments, the Bowtie now leads Honda by 1309 to 1029 in the manufacturers’ standings.