CROWN POINT, Ind. (CBS/AP) — A former sheriff’s officer has pleaded guilty but mentally ill to drunk driving charges from a hit-and-run crash after the Gary Air Show in 2016.

Former Lake County Sheriff’s Lt. Guy Mikulich was sentenced to 2 1/2 years in the Lake County Community Corrections program as part of the plea agreement. He will begin his sentence under home detention, including a year wearing an alcohol monitoring bracelet. He also was sentenced to an additional 2 1/2 years of probation.

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Lt. Guy Mikulich (Credit: Lake County Sheriff)

Police said Mikulich had a blood alcohol level nearly twice the legal limit when he hit Derrick Dircks, of Frankfort, Illinois, just blocks from the Gary Air Show at Miller Beach in July 2016. Witnesses said Dircks was packing up his van with his family, when a black Ford Crown Victoria hit him from behind.

Dircks survived, but was seriously injured.

Mikulich kept going after hitting Dircks, and was arrested a short time later. He was wearing his uniform and driving his unmarked squad car.

He had been working the air show minutes before the crash. Police said his blood alcohol level was 0.15, almost twice the legal limit of 0.08.

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Mikulich pleaded guilty but mentally ill on Monday to charges including leaving the scene of an accident with serious bodily injury and operating a vehicle while intoxicated.

As part of the plea deal, Mikulich will undergo psychiatric treatment and alcohol treatment, according to published reports. He also reportedly told the court he was suffering from post-traumatic stress and alcohol abuse in the months before the crash; and was experiencing sleeplessness, paranoia, and memory loss.

Mikulich reportedly said his mental problems were made worse by growing tensions between police and the community in 2016, and the day before the crash was at the scene where two men drowned trying to save an 11-year-old boy from rip currents at Wells Street Beach in Gary, and felt unfit for duty the morning of the crash, but was ordered to report to work.

The Lake County Sheriff’s Police Merit Board last year voted to fire Mikulich after finding him guilty of eight disciplinary charges.

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)