Canadian police are investigating whether a beating captured on video and reported to have been distributed through Facebook is connected to a young woman's murder.
The video is the latest example of Facebook being used to document violent crimes, a pattern that has led the company to re-evaluate some of its policies.
"This was a horrific tragedy," Facebook said in a statement emailed to Reuters.
"We have not been able to locate the video on Facebook and are working with law enforcement as they investigate."
Thai police said they would consider how to quickly remove inappropriate online content after a man broadcast himself killing his 11-month-old daughter on Facebook.
Last week, the company said it was reviewing how it monitored violent footage after a posting of a fatal shooting in Cleveland, Ohio was visible for two hours.
The Canadian video showed someone kicking a woman in the face while a second person held back her arm from defending herself, according to Winnipeg Free Press, and was shared through Facebook.
Royal Canadian Mounted Police (RCMP) Sergeant Paul Manaigre said police are reviewing the video to determine whether it is linked to a murder at Sagkeeng First Nation in Manitoba last weekend.
It may have been shared directly between people on Facebook, but not posted for public viewing, Manaigre said.
Police have charged two girls, ages 16 and 17, with the second-degree murder of a 19-year-old woman in Sagkeeng.
- Reuters, AAP