During the annual F8 developers conference on Tuesday, Facebook CEO Mark Zuckerberg made a cursory mention of a murder video posted to Facebook, saying the company would do everything to prevent such tragedies.

“We have a lot of work, and we will keep doing all we can to prevent tragedies like this from happening,” Zuckerberg said on stage at F8, Facebook’s annual developers conference.

“Our hearts go out to the family and friends of Robert Godwin Sr,” Zuckerberg added.

He opened his keynote with jokes about Fast and Furious. He spoke briefly about building community before addressing the Cleveland murder, CNN reported.

On Sunday, 37-year-old Steve Stephens murdered an elderly man in Cleveland, Ohio, and then posted the video of the crime on Facebook.

The shooter, who appeared to choose his victims at random, also posted that he had killed 12 people in all and vowed to continue killing.

Stephens was found dead after a brief police pursuit in the US state of Pennsylvania.

The news of his death broke just an hour before the conference kicked off.

Facebook came under severe criticism for not removing the murder video for more than two hours.

“We know we need to do better,” Justin Osofsky, vice-president of global operations at Facebook, wrote in a post on Monday.

Facebook is said to have thousands of people reviewing content around the world.

“Once a piece of content is reported by users as inappropriate, it is typically reviewed within 24 hours,” the report noted.

Earlier, Zuckerberg had said that Facebook was developing artificial intelligence to better flag content on the site.

“This system already generates about one-third of all reports to the team that reviews content,” Zuckerberg’s said.

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