Annotated with a guinea pig, drawn by Ms Curtis to calm the girl, it was leaked on the authority of former Immigration Minister Lianne Dalziel, who lied to NZPA about how TV3 had got it.
In his findings, Mr Toogood was not critical of NZIS or electorate office staff.
He had difficulty establishing just who had sent the letter to the electorate office, Mr Wintringham said.
"Whilst there are some conflicting recollections regarding certain events, the inquiry revealed no improper behaviour by Immigration Service officials," he said.
The report showed Parliamentary Services staff "tread a fine line" in their job, he said.
There was no criticism of electorate office staff in passing on the letter to the minister, he said.
Ms Dalziel resigned in February after admitting she had lied to the news media about leaking the letter to discredit lawyers acting for the girl.
Ms Dalziel said she was sent the letter from the Mt Albert electorate office, but lawyer Carole Curtis denied having ever sent it there.
Ms Curtis alleged Immigration Service officials must have taken it from her client's belongings at the Mangere Refugee Centre.
The terms of reference were:
* the circumstances in which an employee of the Immigration Service or of the Parliamentary Service (the two electorate office staff) handled or obtained a copy of the annotated letter;
* actions taken in respect of the copy of the letter by any such employee; and
* the involvement, if any, of any such employee in the passing of the letter to any party, including the electorate office for the member of parliament for Mount Albert, and/or in the transmission of the letter to the Immigration Minister.
- NZPA
Christopher Toogood QC:
Report for the State Services Commissioner on Inquiry Into Actions of Employees of the Immigration Service and the Parliamentary Service
re leaking of the "guinea pig" letter to the media [PDF]
Herald Feature: Immigration
Related information and links