The incident was reported around 3:30 p.m. in the 300 block of South Huntington Avenue, between Arrow Highway and Cienega Avenue.
Cell phone video obtained by Eyewitness News shows a woman carrying what appears to be a Samurai sword before LA. County Sheriff's deputies stop her in the middle of the street.
"I heard the sirens around and then I heard the police saying get down, get down," said San Dimas resident Trinh Garcia.
Garcia was home when the incident happened. At the time, she didn't know the woman was carrying a sword nor that another woman from the same home had been killed.
"We are shocked, we are stunned," Garcia said.
"Upon arrival, deputies find a female suffering numerous cuts and lacerations on her body. That female then directs them to a residence on the street where the deputies find an additional female suffering also from lacerations, was later pronounced dead at the scene," said LASD Lt. Daniel Vizcarra.
Deputies then found another woman as they searched the home who was unharmed but also transported to the hospital due to a medical emergency, Vizcarra said.
It was not immediately known if the woman caught on video walking with the sword was a victim or a suspect. Additional video showed her walking up to the front door of a home a few doors down with blood streaming down one arm and carrying the sword in the other.
"Didn't know what was going on, and didn't recognize the lady, thank goodness we weren't home. She just said hello, hello. Maybe she was just crying for help, but at the same time I'm thinking why does she have a sword?" said area resident Ed Consencino.
Neighbors said the people involved in this incident lived at the same home, however, what happened inside that home on Thursday remains unclear.
"They were quiet people, they only came out to get the mail, open the garage, take the trash out, other than that, they were quiet people," said Garcia.
No arrests have been made and no further details were immediately available.
Anyone with information is urged to call the Los Angeles County Sheriff's Department's Homicide Bureau at 323-890-5500. You can also submit an anonymous tip by calling Crime Stoppers at 800-222-8477 or visiting lacrimestoppers.org.