Officers were contacted with reports of a man seen in Colchester, thought to resemble one of the offenders involved in the attempted abduction in Norfolk.
A victim was threatened with a knife by two men who tried to force him into a car near the Norfolk base last week.
Police investigating the incident at RAF Marham confirmed the sighting was not one of the suspects.
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The Norfolk force issued an e-fit earlier this week in an attempt to track down the two men, who fled the scene in a dark-coloured people carrier, which the police are still trying to trace.
A Ministry of Defence spokesman said safety of personnel was "paramount".
A sighting of a man near a barracks is not linked to an investigation into a kidnap bid at RAF Marham, police said.