Alleged fatal arsonist caught on camera starting blaze

Warning: This video contains graphic images which may disturb some people.

A Wisconsin woman has been filmed appearing to pour gasoline through an open window of a house before setting it on fire.

A 39-year-old woman has been detained in relation to the blaze in Malwaukee but local police were unable to comment on if it was the same woman seen in the video.

The unnamed woman can be seen smashing the window and throwing something inside, before leaving and returning with a gas canister in hand.

"Oh my god, she's going to set that f**king place on fire," the woman filming can be heard saying.

After pouring the gasoline in through the window the woman can be seen starting a fire, sending flames bursting through the window, to the horror of onlookers.

As the blaze intensifies a woman can be seen jumping to safety out of the window, with witnesses rushing to help in desperation.

At one point they smash down the front door to try and get inside to help people, sending plumes of black smoke furling out.

One person was killed in the blaze, 72-year-old Willie Greer.