FIRST MINISTER DESIGNATE Michelle O'Neill has criticsed the decision to approve a Public-interest immunity (PII) certificate in relation to the Noah Donohoe case.
The Sinn Féin Vice President has written to newly-installed Secretary of State Shailesh Vara asking him to withdraw his approval for the certificate.
It follows a similar call from party colleague Gerry Kelly, MLA for North Belfast and a member of the Policing Board, who urged the PSNI to withdraw its PII application.
A PII certificate is a court order allowing a litigant to refrain from disclosing evidence to other litigants on the basis that it would be damaging to the public interest.
Ms O'Neill has said the decision to grant one in relation to the Noah Donohoe case 'unacceptable'.
"I have written to British Secretary of State Shailesh Vara today (Friday) making it clear that the use of a Public Interest Immunity (PII) certificate to conceal information on the death of Noah Donohoe is totally unacceptable," she said.
"We are talking about the tragic death of a 14-year-old child, his family deserves to have truth and transparency on what happened to this little boy.
"I previously raised my concerns on the matter with Chief Constable, Simon Byrne and Deputy Chief Constable, Mark Hamilton where the case has been put that any application for a PII certificate is wholly inappropriate and is adding significant distress to the Donohoe family.
"The application should be withdrawn immediately.
"I will continue to support Noah's mum and his family every step of the way in their search for truth, transparency and accountability."
Mr Kelly previously criticised the use of a PII certificate in the Donohoe case, saying they are normally used in Northern Ireland 'to hold back information in conflict legacy cases'.
"This inquest is about the death of a 14-year-old child. It is not conflict related," he said.
On the day he disappeared, he had been cycling to meet friends to carry out work for his Duke of Edinburgh Award.
A post mortem determined he had drowned, while police do not believe foul play was involved in his death.