A man accused of stabbing three people in a random attack at a gym on Sydney's northern beaches on Monday night is then believed to have carried out two armed robberies at service stations just hours later, police say.
Police are now hunting for the "agitated and aggressive" man, described as having a full beard and aged in his mid to late 20s, who allegedly attacked the men in the gym at Brookvale before driving to Newcastle in a stolen vehicle and robbing the service stations.
Members of the public who see the man or the stolen black BMW he was driving have been advised not to approach him, but to call triple zero immediately.
Police say the man's alleged rampage began in Brookvale just after 8pm on Monday, when he entered the Plus Fitness gym on Pittwater Road where four men were working out with a trainer.
Witnesses said the offender appeared to be extremely agitated, before he approached one of the men who was working out and punched him.
He then pulled out a knife and attacked three other men, stabbing one in the neck and two others in the arms. Their trainer was not injured.
The injured men ran outside and called police, and their alleged attacker escaped in a stolen black BMW, with NSW registration plates DKK 39Q.
The stabbing victims were taken to Royal North Shore Hospital. One of the men needed emergency surgery, while the other two were in a stable condition. None of their injuries are life-threatening, a NSW Police spokeswoman said.
Police said at 9.45pm on Monday, less than two hours after the stabbing, a black BMW pulled into a service station on Maitland Road in Sandgate, in Newcastle's north, and the driver started filling up the vehicle with fuel.
A 38-year-old employee at the service station thought the driver was acting suspiciously, and started to approach him.
The man then allegedly followed the woman back into the service station, threatened her and started smashing the cash register. The woman told police the man pulled out a knife and stole money from the cash register, before driving away.
About 15 minutes later, the same man is believed to have walked into another service station on Maitland Road and placed two chocolates on the counter.
As the 24-year-old employee opened the cash register, the man jumped onto the counter, pulled out a knife and demanded the employee hand over cash. The employee did so, before the offender ran from the station and got back into his vehicle.
Police who were responding to the report of the first armed robbery saw the stolen BMW and started chasing it, but the vehicle got away.
The descriptions of the offender and vehicle from both the Brookvale stabbing and the service station robberies were the same.
Police described him as being Caucasian, about 168 centimetres tall, aged in his mid to late 20s with a full beard. He was wearing black shorts and a light coloured T-shirt at the time.