12/27/2012 01:02 pm ET Updated Dec 28, 2012

Homeless Woman Set On Fire While Sleeping On Bench In Van Nuys, Calif. (VIDEO)

A homeless woman is fighting for her life after being set on fire while sleeping on a bus bench in Van Nuys, Calif.

The horrific crime occurred at about 1 a.m. Thursday when the suspect, believed to be 28 years old, walked into a Walgreens store and bought alcohol, KTLA reports. He then poured alcohol on the woman, lit a match to set her on fire, and ran.

But a witness, Erickson Ipina, was able to chase him down.

"I was following him and then I pulled out my cellphone. I called 911 and he just turned back on me and pulled out a knife, and he told me, 'Stop following me or I will cut you,'" Ipina told ABC.

But Ipina continued to follow the suspect until police arrested him. Investigators are trying to determine the suspect's motive.

The victim, a 67-year-old homeless woman, is in the hospital with extremely severe burns, and it is not clear if she will survive.

Last week, a 55-year-old man was set on fire as he slept outside a donut shop in southern LA County, the Associated Press reports. No suspects were arrested for that incident.

Between Dec. 2011 and Dec. 2012, four homeless men in LA were murdered on individual occasions. The suspect, Itzcoatl Ocampo, who was discharged from the Marines in 2010, is awaiting trial as the suspect in the murders.



Photos from the slew of LA homeless murders between Dec. 2011-2012:

Serial Killer in the OC