Homicide Squad detectives have released new images of wanted man Shawn Adam Newton, who they say may be committing other crimes while eluding police.

Mr Newton, 42, has been wanted for more than a week in relation to the death of 35-year-old mother of three Rebecca Jane Gascoigne, whose body was found in a car on the Mitchell Freeway on July 15.

Officers are now investigating whether Mr Newton was linked to an armed robbery on Sunday night at a fast food outlet in Duncraig.

In the robbery the offender was wearing a black balaclava and a blue jacket with a white and red stripe on the arm.

He was carrying a red bag and threatened staff with a firearm before demanding cash and fleeing the store in a southerly direction.

"We are also investigating a number of burglary offences that Mr Newton may be linked to during the past week," Detective Senior Sergeant Dean Bailey said.

"It is common for people who are actively trying to elude police to commit crimes in an effort to support themselves."

Det-Sen Sgt Bailey said anyone helping Mr Newton may also be at risk.

Mr Newton is described as fair skinned, about 186cm tall, with a medium build, very short dark hair and brown eyes.

He may be in possession of a firearm, may have grown facial hair and may also be using wigs to disguise himself.

Anyone who sights him is urged to not approach him and instead call police on 131 444.