Whoever sent a potentially fraudulent email put forward as evidence at an inquest in Wellington could wind up in jail.
The message, supposedly written by an aviation school's senior manager, was presented at the hearing into a mid-air collision over Paraparaumu in 2008.
An Auckland solicitor, Chris Morris, says charges could include perverting the course of justice or fabricating evidence, which comes with a term of up to seven years' imprisonment.
Mr Morris says the incident is highly unusual, though it doesn't suggest any problems with the way in which evidence is provided to coroners' courts.
Police are investigating and the Wellington coroner's office says the hearing will resume in December.