Sussex Police have arrested two further men in connection with the damage of post boxes and telephone kiosks in the Chichester district.
A 22 and 23-year-old man both from Chichester were both arrested on suspicion of causing explosions likely to endanger life or injure.
The arrests come after eight postboxes and telephone kiosks were damaged in Bosham, Lavant, Charlton, East Dean and Oving on Wednesday, December 26.
Detective Sergeant Vicky Guy said: “We have now made a total of five arrests but this still remains a live investigation
“We continue to appeal to the public and ask anyone with information to report it to us without delay.
The two men were released on police bail until February 8.