Three men and a woman have been arrested in connection with an armed robbery in Cornwall last Friday.
Three were detained in Weston-super-Mare, Somerset, and the other was taken into custody at Newquay overnight.
A shot was fired during the robbery at the Kingsley Service Station in Fraddon on Friday night.
The offenders got away with cash and cigarettes.
Officers say the four people arrested will be questioned about the incident on Wednesday.
They will also be questioned about an attempted murder in St Dennis on 20 December.