The sister of one of the black police officer slain in Baton Rouge has revealed she was sitting in church when she learned her beloved brother had died – when the pastor asked the congregation to pray for her family.

Montrell Jackson, 32, was one of three officers killed by shooter Gavin Long, on Sunday morning.

Unaware that her brother had died, Joycelyn Jackson arrived at an afternoon church service after the pastor had been informed of Jackson's death by her other brother, the Washington Post reports.

When the pastor asked other churchgoers to direct their prayers to her family, she was devastated to realize what had happened.

‘I didn’t want to break down in church, but it was just something I couldn’t hold,’ she said. ‘It’s coming to the point where no lives matter, whether you’re black or white or Hispanic or whatever.'

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Joycelyn Jackson (left) revealed she was sitting in church on Sunday when she learned that her brother Montrell Jackson (right) had died because the pastors asked the congregation to pray for her family

The 49-year-old says that although she understands the anger that fuels the Black Lives Matter movement, ‘God gives nobody the right to kill and take another person’s life.’

Joycelyn, who lives in Lake Charles, Louisiana, described her younger brother as a ‘wonderful person.’

Asked if she could speak to the man who killed her brother – or anyone else considering harming police officers – she said she would urge them to ‘get their lives right with God.’

She added: ‘Hell is a horrible, horrible place to be.’

Despite her brother being a 10-year veteran of the police force, Joycelyn said she was never concerned for his well-being until the recent tensions between law enforcement and the black community.

Baton Rouge has seen a wave of protests over the treatment of black people by police since the death of Alton Sterling, 37, a black man who was killed by two white officers on July 5.

Jackson was a 10-year veteran of the police force and had recently had a baby son named Mason (above)

Jackson recently shared a poignant message on Facebook about the struggles of being a black police officer in Baton Rouge after a sniper attack in Dallas during a Black Lives Matter protest left five cops dead

Jackson himself recently shared a poignant message on social media about the struggles of being a black police officer in the city shortly after a sniper attack in Dallas during a Black Lives Matter protest left five officers dead.

He said he was both physically and emotionally drained by it all.

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

‘I've experienced so much in my short life and these last three days have tested me to the core.

Gavin Long (above) was named as the gunman who killed three police officers and wounded another three on Sunday

'When people you know begin to question your integrity you realize they don't really know you at all.

'Look at my actions they speak LOUD and CLEAR.’

He added: ‘These are trying times. Please don’t let hate infect your heart. This city MUST and WILL get better.’

Jackson was a new father who adored his four-month-old son. He and his wife Trenisha welcomed baby Mason in April.

The new father towered over most people at 6ft 3, but Joycelyn remembers him as the little boy who was a picky eater.

Lonnie Jordan, Jackson's father-in-law, said he was also at church when he learned about his death when he received a text message.

Jordan described his son-in-law as a ‘gentle giant’ – tall, stout and formidable looking, but with a peaceful disposition. He was ‘always about peace,’ Jordan said.’

He said his son-in-law had been working long hours since the death of Sterling and the resulting protests – but if the work was a strain, Jackson didn't let it show.

Jackson’s younger half-brother Kedrick Pitts, 24, said the pair were very close.

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

He said his brother joined the police force in 2006 and had risen to the rank of corporal.

Pitts said he woke up on Sunday to find his mother crying as news broke about the shooting.

He drove his mother to the hospital and it was there that they discovered that Jackson had been shot.

Jackson and his family were planning to go to Houston soon for a vacation, Pitts said.

Matthew Gerald (pictured left) and Brad Garafola (right) were also killed in Sunday morning's attack

Pitts was stunned by his brother's death, but put on a brave face and did not shed any tears. "I did all the crying I can do. It's not going to bring him back," he said.

He described his older brother as someone with a humorous streak but a serious side – as well as a hard-working police officer who often worked seven days a week.

He said he was fond of shoes and had a collection of more than 500 pairs - such as special Kobe Bryant and Michael Jordan sneakers. He said his brother was a big fan of the New Orleans Pelicans and the Dallas Cowboys.

A GoFundMe page set up by a family member to raise funds to help Jackson’s widow and newborn son Mason described him as a hero.

‘Words cannot describe the devastation we fell right now,’ a post on the page said. ‘Rest in peace, Montrell, you will always be our hero.’

Friends and family have also paid tribute to the other officers slain by a gunman who opened fire on officers after they responded to a call to a gas station along Airline Highway.

Jackson's fellow Baton Rouge police officer Matthew Gerald, 41, and Brad Garafola, 45, of the East Baton Rouge Sheriff’s Office, both died.

Three other officers were shot, with one said to be in critical condition.

Gerald, 41, was a married father-of-two and joined the force last year after serving in the Marines and the Army. He had been deployed to Iraq three times.

Father-of-four Garafola, 45, had worked at the sheriff’s office for 24 years.