A GoFundMe page crosses six figure mark after killing of Jemel Robinson while he was subduing a suspected gunman.

A fundraising page has raised more than $121,000 for a black security guard killed by a white police officer while he subdued a suspected gunman at a bar in Chicago.

Jemel Roberson apprehended the man who had fired shots inside the bar on Sunday, but when police arrived at the scene they shot the 26-year old as he held down the attacker.

The shooting suspect left at least four people inside the bar wounded.

According to local media reports, witnesses shouted “security” at the police officers in a vain attempt at stopping them from firing their weapons.

“Everybody was screaming out, ‘Security!’ He was a security guard,” witness Adam Harris told WGN9.

“And they still did their job, and saw a black man with a gun, and basically killed him,” he added.

Midlothian Police said one of their officers shot Roberson after he ignored multiple requests to put down a firearm that he was licensed to carry. The department confirmed that the officer was white.

Roberson, a father of one whose partner was pregnant with his second child, died in hospital after receiving multiple bullet wounds.

‘Intentional, willful, and wanton’

A lawsuit has been filed against Midlothian Police for their role in Roberson’s death and the officer responsible has been placed on administrative leave, according to local media.

A lawyer for Roberson’s family said his killing was “intentional, willful, and wanton,” the Chicago Tribune reported.

Friends described Roberson as a “church-going guy” and devoted father, who had dreams of joining the police.

His death is the latest of a black man at the hands of a US police officer, and the circumstances of Roberson’s killing have prompted renewed focus on police violence in the country.

According to the Washington Post’s Fatal Force database, at least 841 people have been killed by the police in the US this year. The Post found that more than 980 people were killed by police in 2017.

The Guardian identified more than 1,090 police killings the previous year.

Nearly a quarter of those killed by police in 2016 were African Americans, although the group accounted for roughly 12 percent of the total US population.

According to watchdog group The Sentencing Project, African American men are six times more likely to be arrested than white men.

These disparities, particularly the killing of African Americans by police, has prompted the rise of the Black Lives Matter movement, a popular civil rights movement aimed at ending police violence and dismantling structural racism.

“Jemel Roberson was a young father and a security guard who aspired to one day become a police officer,” said Democrat New Jersey Senator Cory Booker on Twitter, adding: “He was doing his job, subduing a shooter, when he was killed by a police officer.

“Words can’t begin to describe my horror and outrage.”