The man who killed Officer Natalie Corona in an “ambush”-style attack left a note in the apartment where he killed himself, claiming that police had targeted him with “ultra sonic waves meant to keep dogs from barking.”

The note left by Kevin Douglas Limbaugh of Davis, Calif., was released after Davis police identified the 48-year-old as the man who fatally shot Corona during the officer's response to a car collision Thursday night.

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Kevin Douglas Limbaugh claimed in a note that Davis Police had hit him with "ultra sonic waves" before fatally shooting Officer Natalie Corona. (Davis Police Department )

“The Davis Police department has been hitting me with ultra sonic waves meant to keep dogs from barking,” reads the note, which was typed on a computer. “I notified the press, internal affairs, and even the FBI about it. I am highly sensitive to its affect (sic) on my inner ear. I did my best to appease them, but they have continued for years and I can’t live this way anymore.”

There’s no way to know when the note was typed, Davis police Lt. Paul Doroshov told SFGate.com, adding that the note was found during a search of Limbaugh's apartment.

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“There have been a lot of rumors as to why this happened, why he did what he did, and we’re hoping this sheds some light,” Doroshov said. “As for the placement of the note, which was found face-up on Limbaugh’s bed, “I really can’t speculate as to why it was there like that.”

In addition to the note, officers found two semiautomatic handguns inside the house, a 9 mm and a .45-caliber, Doroshov told the Sacramento Bee.

According to authorities, Limbaugh rode up on a bicycle and shot and killed Corona as the rookie cop was on the scene of a three-car collision. He then unleashed a barrage of bullets that struck a bus, firetruck and a young woman’s backpack. The woman with the backpack was uninjured.

He then fled to a rental home he shared with a roommate. At one point, Limbaugh emerged from the home wearing a bulletproof vest and yelled at the officers before going back inside. He emerged a second time with a gun before retreating.

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The officers never fired at him.

After hearing a single gunshot inside, the officers sent a robot where Limbaugh was found to have fatally shot himself in the head.

The shooting wasn’t Limbaugh’s first brush with the law. The Sacramento Bee reported he was charged and convicted on a battery case last fall in which he assaulted a co-worker in the face after a dispute. As part of that case, Limbaugh was ordered to surrender an AR-15 rifle, the report said.

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More than 1,000 mourners attended a Saturday evening vigil for Corona. The event was filled with speeches by local politicians and musical performances, according to the Bee.

What brings us together is a really, really sad incident and one gathering is not going to change that,” Davis Mayor Brett Lee said. “But just seeing you all here does make a difference.”

The Associated Press contributed to this report.