John Pat Cunningham was killed in Benburb, County Tyrone, on 15 June 1974.
The case has been reopened by the PSNI's Legacy Investigation Branch and a murder investigation has begun.
The suspect has been brought to Northern Ireland and is being questioned at Antrim PSNI station.
Police investigating the murder of a 27-year-old man shot dead by soldiers more than 40 years ago have arrested a 73-year-old man in England.