Alberta Health Services said an investigation into an address error that was posted online, found the mistake came from a form that had been filled out a decade ago.

Wapayos Iskwew posted a photo of the AHS letter in an envelope Wednesday afternoon. In place of her 15-year-old daughter’s name, the letter was addressed to ‘Treaty Indian’.

Her post was shared hundreds of times and garnered dozens of comments, most condemning AHS for the error.

AHS issued a public apology on Facebook Thursday, and said they had been notified of the issue the day before, and had apologized to the family and “apologized to members of the First Nations, Indigenous and Métis communities.”

In another post later Thursday, AHS released details on their investigation into the matter.

AHS said the error stemmed from a form that had been filled out for a patient record for a hospital visit ten years before – when “historical wording related to Treaty status was entered into the wrong field on a patient record.”

At a more recent hospital visit, AHS said their computer system had copied that wording over, and it was included on an invoice sent to the patient.

The statement called the error “inexcusable.”

“The wording is absolutely not language that we would purposefully use. It is inappropriate, insensitive and should not be used in any circumstance.”

AHS said the invoice related to this case had been waived.