A man live-streamed his violent suicide on Facebook - just days after another man broadcast himself killing his baby daughter on the social media site.
James Jeffrey, 49, shot himself in the head at his home in Alabama on Tuesday night in a video that was viewed more than 1,000 times before being removed by Facebook after two hours.
A series of calls to the local emergency services were logged from Facebook users saying they had seen the incident.
Anthony Lowery, assistant chief deputy with the Baldwin County Sheriff's Office, told USA Today: "This was a first for us, I hope this isn't a trend starting.
"It's one thing to commit suicide. It's another thing to victimise other people."
He added that law enforcement officials are concerned others may take their lives this way unless Facebook monitors violence on its platform.
Facebook has not yet commented.
Last week, Facebook said it was reviewing how it monitored violent footage and other objectionable material after a posting of the fatal shooting of a man in Cleveland, Ohio was visible for two hours before being taken down.
Facebook founder Mark Zuckerberg said last week his company has "a lot of work" to do on monitoring broadcasts.