By Leah Asmelash, CNN -

Airbnb is cracking down on unauthorized house parties after five people were shot and killed five people were shot and killed at a Halloween party at an Airbnb rental house, the company's CEO announced Saturday.

The company is banning "party houses," CEO Brian Chesky announced Saturday on Twitter, in reference to Thursday evening's shooting.
 
Airbnb will be "redoubling our efforts to combat unauthorized parties and get rid of abusive host and guest conduct, including conduct that leads to the terrible events we saw in Orinda," he wrote. The shooting took place in Orinda, California, a town east of Berkeley in the San Francisco Bay Area.
In additional tweets, Chesky detailed the company's course of action. Anyone found in violation of the upgraded policies could be removed, he said.
 
 
The shooting occurred during a Halloween party Thursday night. The party, held at an Airbnb rental that specifically prohibited parties, was advertised on social media and had more than 100 people in attendance.
 
"Arriving officers found a highly chaotic scene that included gunshot victims, injured party-goers, and numerous people fleeing the scene. The partygoers apparently came from throughout the Bay Area for the Halloween event," a statement from the Contra Costa County Sheriff's Office said.
 
Three people died at the scene and two others died at the hospital, according to the sheriff's office. It's currently unknown how many were injured.
 
The sheriff's office said several of the injured were taken by ambulance to local hospitals by ambulance, while some victims transported themselves to the hospital.
 
The incident is under investigation and no suspects have been arrested, according to the sheriff's office.