Just after 11pm on Thursday, 15 October 2020 police were called to licenced premises in Throssell Street, Collie.
Police were responding to reports of a traffic crash involving pedestrians as well as a possible wall collapse.
Two women, 18 and 23 years were injured in the incident.
The 23-year-old woman was flown to Royal Perth Hospital in critical condition.
The 18-year-old woman was conveyed to Collie Hospital in a serious condition.
A man is assisting police with their inquiries.
Police have closed Throssell Street in Collie, between Mungalup Road and Steere Street South, as investigations continue.
Anyone who witnessed the incident is asked to call Crime Stoppers on 1800 333 000 or report online at www.crimestopperswa.com.au.
Last call for donations to support Mandurah's homeless
State Government commits to building $5 million electrical training facility at Rockingham TAFE
McDonald's approved for Dawesville
Wanted man known to frequent Kwinana, Mandurah and Rockingham areas
Mandurah woman completes grueling English Channel swim
Man and child seriously injured in South West crash
Motorists warned to expect delays during Kwinana Freeway upgrades
Driver injured in Serpentine crash
Man and woman wanted for questioning over Lakelands car theft