William, 17, who embroiled his father in controversy last December when he received a caution for selling cannabis in a pub, made the complaint last November after witnessing an incident involving Chelsea fans at Euston station in London.
He is expected to be interviewed about the incident, which was filmed on closed-circuit television cameras, next week.
Officers were escorting the fans back to London from a match against Blackburn Rovers, the team William supports, when trouble broke out on the train. Police were waiting on the platform at Euston and made two arrests.
William, a passenger on the train, saw what happened and later made a complaint against four officers alleging that excessive force had been used in the incident.
John Callendar, acting superintendent of British Transport Police, said: "We can confirm that a complaint was received from a passenger on the train." He added that a complaint had also been lodged by one of those arrested, but it had since been withdrawn.
"The outstanding complaint is being investigated under the normal ... procedures and the complainant will be interviewed, probably next week."
A Home Office spokeswoman said that the issue was a private matter for the Straw family.