Warning: This story deals with suspected suicide and may be upsetting.
A mental health facility was severely short staffed when Nicky Stevens died after going on unescorted leave - and notes from his last days alive went missing.
New evidence from a former nurse at the Henry Rongomai Bennett Centre has been placed before coroner Wallace Bain in an inquest into Stevens' death in March 2015.
The nurse has told of a short-staffed ward 35 where Stevens was being treated for paranoid schizophrenia when he was granted unescorted leave against his family's wishes.
The day Stevens went missing, on March 9, another nurse filed a report about under-staffing, according to the evidence of the former nurse, who has name suppression.
However, after Stevens went missing, that report - and Stevens' detailed daily notes from March 7 to 9 - disappeared.
The matter was only discovered when Waikato District Health Board told police months later.
The nurse said staff on the ward were "blown away" when they were told about the missing notes.
"From my point of view it was a weird thing to go missing."
She said the day after Stevens went missing, the 21-year-old's dedicated nurse and a psychiatric assistant were standing beside the notes on a table, talking.
"By 11am I saw that the notes were gone."
She overheard that the notes had been moved to the charge nurse manager's office.
"When I heard this conversation I asked why they were in [the charge nurse's] office and was told by the shift manager that they would be protected in there."
On the day Stevens' body was found in the Waikato River in Hamilton on March 12, the nurse said mental health managers descended on the medium-security ward.
She claimed two of those managers went in and out of the office containing the notes.
The next day one of those managers took charge of the notes, explaining they would be "kept safe".
The nurse said she came forward so late in the coronial inquiry because she didn't think her evidence was relevant.
She did not take the witness stand at the inquest at the High Court in Hamilton and was not questioned over her evidence.
However a current Waikato DHB mental-health nurse also gave a statement to the inquest.
She also did not take the witness stand but disputed the former nurse's evidence, saying she never ordered the other nurse to "keep her mouth shut" about the missing incident form.
"It never occurred. Nor would I have a conversation like that."
The three-day inquest is set to conclude today.
Stevens' father Dave Macpherson is giving evidence today.
Where to get help
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
OR IF YOU NEED TO TALK TO SOMEONE ELSE:
• LIFELINE: 0800 543 354 (available 24/7)
• SUICIDE CRISIS HELPLINE: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757