Police have referred an A-level maths paper leak to prosecutors, says an exam board.
Pearson, owner of the Edexcel exam board, says the case sent to the Crown Prosecution Service relates to a leak from an exam taken in summer 2017.
The exam board says the maths paper was seen by a "very small number" of candidates when it was put online in advance of students sitting the exam.
A separate A-level maths leak in 2018 is still under investigation.
In response to the leaks, 14 exam candidates were disqualified in 2017 and a further 15 were disqualified in 2018, says Pearson.
"This is a critical development as it helps ensure that vital public confidence in the examination system is upheld," says a statement from the exam board.
Pearson says the police are "finalising their investigation" into the more recent leak in summer 2018 and the firm says it hopes "they will soon be sending materials to the CPS".
The exam board has written to students and parents emphasising the importance of ensuring the security of exam papers.
Pearson says it recognises "these incidents impacted public confidence" and that those responsible should be held to account.
The 2017 leak was described by the exam board as a "limited breach with isolated individuals gaining access to the paper and sharing it via social channels in advance of the exam".
At the time when the leak was uncovered, Pearson's president, Rod Bristow, said the posting of the paper online had happened when it was "too late to replace papers".
Two questions were changed on the exam paper in a "small number" of schools and colleges where there had been concerns.
Mr Bristow had expressed his "profound regret" but there had been complaints from teachers' leaders about the administration of exam papers that summer.