The first time the Attorney General’s Office advised the Department of Corrections on calculating prisoner sentences in line with a 2002 Supreme Court decision, they got it right.

They told them they’d likely need to do them by hand until computers got reprogrammed.

The next time it came up, on Dec. 7, 2012, they got it wrong, according to an internal review released Thursday by Attorney General Bob Ferguson.

An assistant attorney general told corrections officials in an email that day that they didn’t need to manually recalculate every prisoner’s sentence since a computer update was anticipated soon.

That flawed legal advice contributed to what turned out to be a three-year delay in the Department of Corrections fixing the problem while up to 3,200 prisoners got out early by mistake, the review concluded.

“This legal advice failed the people of Washington and our client, DOC,” Ferguson wrote in a letter accompanying the 48-page report. “By advising the client that it was “reasonable” to not immediately correct this violation of the law, the advice jeopardized public safety and potentially increased liability for the state.”

Ronda Larson, the assistant attorney general who provided the legal advice, resigned in February.

Neither the report nor the letter indicates if Ferguson disciplined any employees based on the findings.

Ferguson ordered the review in December when the magnitude of the mistake – and the lengthy delay in correcting it – became public.

Nineteen current and former employees of the attorney general’s office and corrections department were interviewed, more than 20,000 emails reviewed, and 13 years of records and legal advice analyzed.

It places nearly all the responsibility on Larson for delivering what it deemed “deeply flawed” advice.

While Larson did copy her supervisor, Senior Counsel Paul Weisser, on the Dec. 7 email, he did not recall seeing it nor did she follow procedures by discussing the advice directly with him, the report concluded.

“Our investigation found that the legal advice provided in 2012 was isolated,” Ferguson wrote in the letter. “No one in senior agency leadership, including then Attorney General Rob McKenna, was aware of the problem or the provision of the advice. In fact, despite clear expectations that all legal issues involving significant implications for the state should be elevated to the division chief, the AAG did not identify the sentencing calculation error as an issue that needed to be raised.”

One employee, senior counsel Dan Judge, told those conducting the review that on Dec. 7, 2012, he spoke separately with Kathy Gastreich, risk management director for the DOC, and Senior Assistant Attorney General Tim Lang on the potential liability of early releases due to miscalculated sentences. But neither Lang nor Gastreich recalled such conversations and those conducting could find no evidence to corroborate Judge’s recollections.

As a result of the review, Ferguson said changes are being made. Attorneys will receive more training and the department is creating a best practices guide for providing advice to clients.

Also, the office is requiring any advice from an assistant attorney general to the Department of Corrections on prisoner release dates or other significant issues be reviewed and approved by a supervisor. This was a recommendation from the investigation into the errors conducted on behalf of the governor’s office.