Four people are being questioned about armed robberies at two garages in Denbighshire this week.
On Tuesday a masked man armed with a "cross bow type weapon" raided a garage in Denbigh.
The next day two men wearing ski masks and carrying what appeared to be a handgun struck at a petrol station in Ruthin.
Police say armed and unarmed officers have executed search warrants in the area and made four arrests.
A 20-year-old man, a 23-year-old man, a 20-year-old woman and a 36-year-old woman are in police custody.
But officers are still appealing for information.
Superintendent Andy Jenks-Gilbert said: "The police are extremely grateful for the response from the local community in Denbigh and Ruthin in relation to information concerning recent robberies at commercial premises in the area.
"During the evening of 30 December armed and unarmed officers were involved in an operation where a number of search warrants were executed at addresses in the local area.
"As a result four people are in custody in connection with the robberies and enquiries are continuing.
"The assistance of the public is still sought."
Contact North Wales Police on the non-emergency number 101 or the Crimestoppers charity anonymously on 0800 555111.