A man who was trying to clear a Darwin street of a bicycle “strategically placed” as an obstacle by four alleged youth offenders aged as young as 11 who had just crashed a stolen vehicle, was threatened with a machete by the group, who then stole his car and drove off before crashing it, NT Police said.

Detective Acting Senior Sergeant Dale Motter-Barnard said in a statement that four youth offenders – whose sexes were not given – stole a vehicle in Wulagi at an unspecified time on Tuesday morning, and crashed it in an unspecified street in Muirhead.

“The suspects intentionally obstructed the road in Muirhead, strategically placing a bicycle in the middle,” Snr Sgt Motter-Barnard said.

“When a Good Samaritan attempted to clear the road, the group allegedly threatened the driver with a machete before fleeing in the stolen vehicle, leading to another crash in Leanyer.”

Snr Sgt Motter-Barnard said an off-duty police dog handler identified the alleged offenders in Wanguri, and collaborated with Strike Force Trident members to develop an apprehension plan.

Police did not explain how an off-duty police dog handler – who seemed to have their dog with them – identified the young people as being alleged offenders.

“Upon police presence, the group attempted to escape on foot, leading to a pursuit through Casuarina,” Snr Sgt Motter-Barnard said.

Police gave no details of the second crash and if it involved a police vehicle pursuit of the car.

Snr Sgt Motter-Barnard said the youths ignored police instructions to stop, and one was “apprehended” by police dog Drax, while the remaining three were caught by Strike Force Trident members.

Police said one of the youths, an 11-year-old, was returned home to a “responsible adult”, while the other three, whose ages were not given, were in police custody about 2.30pm and were expected to face charges on Tuesday.

What charges they faced was not explained.