A police officer who was killed in a shooting in Baton Rouge had posted a heartbreaking Facebook message saying he was tired both "physically and emotionally."

Montrell Jackson, 32, was shot dead on Sunday along with two other officers by a gunman.

On July 8, he pleaded the embattled community to not let "hate infect your heart" after a black man was shot and killed by police in Baton Rouge.

Tweet may have been deleted

"I swear to God I love this city but I wonder if this city loves me," Montrell Jackson wrote. "In uniform I get nasty hateful looks and out of uniform some consider me a threat."

"I've experienced so much in my short life and these last 3 days have tested me to the core," the post read.

"These are trying times. Please don't let hate infect your heart. This city MUST and WILL get better," he continued and, addressing protesters, officers, friends, family and neighbours he said: "I got you."

A screenshot of the image has been circulating on the internet but it's no longer on Jackson's Facebook page.

Friends and family of Jackson were mourning the 10-year-veteran of the police force that relatives described as a "gentle giant" and a "protector."

Kedrick Pitts, the 24-year-old younger half brother of Montrell Jackson, said he was very close to his older brother.

"With him it was God, family and the police force," Pitts said outside his mother's house in Baton Rouge, where family was gathered Sunday. "He went above and beyond ... He was a protector."

Jackson leaves behind a wife and a 4-month-old son named Mason.

The Associated Press contributed reporting.

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