A state lawyer’s advice not to manually calculate prison releases in light of technical issues — which led to the early release of 3,000 inmates, one of whom killed a Bellevue woman at a time when he should have been incarcerated — “failed the people of Washington and our client, the Department of Corrections,” Attorney General Bob Ferguson said in an investigative report of his office released on April 7.

“Even in a culture of excellence, serious mistakes can happen,” Ferguson said in a statement accompanying the results of his office’s internal investigation.

Former assistant attorney general Rhonda Larson reportedly told the Department of Corrections that it would be “reasonable” for the department “not to manually fix” the incorrectly calculated sentences and should instead wait for the prison sentence calculating program to be fixed.

Larson appeared to believe that the programming error would be resolved in a few months, and had been told by the department records manager in Dec. 2012 that it could possibly be completed in 90 days.

In reality, the reprogramming did not occur for three years.

Between Dec. 2011 and Dec. 2015, more than 1,500 inmates were accidentally released from prison early.

Approximately 80 of those inmates went on to commit other crimes or violate law enforcement requirements set upon them at their release. Among them was Robert T. Jackson, who is accused of having killed a Bellevue resident and mother in a hit-and-run crash that occured when he should still have been incarcerated.

Jackson is currently in jail awaiting trial for Hill’s death. He will have to finish the time owed on his previous sentence, regardless of the outcome of his trial.

In all, 3,200 inmates were accidentally released between 2002 and 2015.

Both Ferguson and Gov. Jay Inslee ordered separate investigations into the issue in Dec. 2015.

“The early release of thousands of prisoners over 13 years was caused by a series of errors coupled with bureaucratic incompetence, systemic failures of process and management, and an inexplicable failure both on an institutional and individual level to appreciate the fact that releasing even one inmate early, let alone thousands, undermined the core mission of the Department of Correction, which is to protect the public,” said the governor’s report, which was compiled by Carl Blackstone and Bob Westinghouse.