Teenage staff have been threatened with kitchen knives and a gun in four "brazen" robberies at fast-food restaurants in 24 hours on Brisbane's southside, police say.
Two young women and a man were filmed by CCTV threatening staff in three outlets including a McDonald's and Hungry Jack's.
Footage shows the trio leaving a fast-food restaurant with what appears to be drinks from the store, and a brown paper bag.
Police said they demanded cash, although the operators do most of their business online and with eftpos, so hold very little money in store.
The first robbery happened about 9:30pm at Springfield.
"Employees were threatened before cash was stolen with the trio then fleeing in a stolen 2003 white Ford Falcon utility with Queensland registration 120-FG7, in a north-east direction onto Springfield Parkway," Acting Detective Inspector Michael Manago said.
"Three fast-food businesses were robbed by the same group on Monday evening between 9:15 and 9:40pm in Rocklea, Salisbury and Algester."
"I would say it is brazen in their action and we are treating it quite seriously. We want to identify these offenders and bring them to justice.
"Any incident with a firearm or dangerous weapon we are very concerned about."
Police could not say if the gun was loaded or if it was a replica.
They are also searching for a fourth offender who waited outside in a stolen getaway car, which was later found abandoned.
It had been stolen from a Carole Park address.
The teenage workers in the targeted stores were shaken by the robberies, he said.
"The staff are young, often it is their first job. They have been left traumatised by what has happened and we are offering counselling to support them."
Police are urging fast-food outlets to be extra vigilant, and are appealing for anyone with information to contact them.
Officers are also doing extra patrols of fast-food outlets.
In a statement, McDonald's Australia said the wellbeing of their staff and customers was a "top priority".
"No one was injured in the incident and we will continue to support all employees working at the time," they added.
