KUALA LUMPUR, May 3 -- A 28-year-old woman armed with a knife was arrested on the final night of the Rain Rave Water Music Festival in Bukit Bintang yesterday, with a viral video showing members of the public bravely intervening to subdue her before police arrived.

Kuala Lumpur police chief Datuk Fadil Marsus confirmed the arrest, which occurred amidst a crowd of approximately 30,000 attendees.

"Tonight, we have arrested a 28-year-old woman for possession of a weapon," Fadil told the media after the event.

"She was found in possession of a knife and has been detained; she will undergo the remand process later in the morning."

The video, which has been widely shared on social media, shows several bystanders holding the woman back, with...