A Queensland police officer has been critically injured in a head-on crash between a police van and a ute north of Brisbane.
Four people were taken to hospital after the crash, which occurred in South Caboolture around 2:50pm.
Police told the ABC the crash occurred as they were trying to respond to a report a man had stabbed his flatmate at Moon Street in Caboolture.
The alleged attacker fled in a car.
Police said while driving along River Road, the man and a police van carrying three officers collided.
Inspector Craig White from Moreton police said they are investigating whether the man deliberately drove into the van.
He said two officers and a police recruit were involved in the crash.
A male senior constable, who was driving the van, suffered critical injuries.
A first-year male constable and a female police recruit were also taken to hospital.
"The recruit was doing the on-road practical training at the time the incident occurred," Inspector White said.
She is due to be sworn in as a police officer on March 24.
Inspector White described the three as being in a "serious condition", although the Queensland Ambulance Service (QAS) said two people were critically injured.
The impact of collision was such that the bonnet and driver's side of the police van was completely ripped off.
Inspector White said the person wounded at Moon Street was also taken to hospital in a serious condition.
"To summarise, you've got three police in a serious condition, you've got one suspect in serious condition as well," he said.
"You've also got a victim of a stabbing who's listed as serious as well."
He said it was not yet clear what happened to a van found damaged at the house where the stabbing allegedly occurred.
"At this stage the investigation will be conducted and overviewed by Ethical Standards Command, which is a normal part of the process involving any police-related traffic accident," Inspector White said.
QAS said one male patient was taken to Caboolture Hospital in a critical condition with head and chest injuries.
Another male patient was taken to the Royal Brisbane and Women's Hospital (RBWH) in a critical condition with chest, leg and arm injuries.
A third male patient was taken to RBWH in a serious but stable condition with facial injuries, while a female patient was taken to RBWH in a stable condition with chest injuries.
