https://www.wired.com/story/spacex-crew-dragon-accident/

During a series of engine tests of SpaceX's Dragon spacecraft this past Saturday, the vehicle experienced what the company has characterized as an "anomaly." Based upon an unauthorized leaked video of the accident, the company was counting down toward a firing of the Dragon's SuperDraco thrusters when the vehicle exploded.

SpaceX has not validated the video, but it is consistent with verbal accounts of the failure that have been shared with Ars.