Three men have been arrested on suspicion of setting off a string of explosions in post boxes and telephone kiosks.
Six post boxes and two phone boxes in West Sussex were hit in the two-hour spree on 26 December.
Two men aged 22, from Chichester, and a 23-year-old from Hampshire were arrested on suspicion of causing explosions likely to endanger life.
They were released on police bail until 5 February.
The explosions, in villages around Chichester, all happened between 22:00 GMT and midnight, causing damage but no injuries, according to police.
But they had a "significant potential to cause injury", a spokesman said.
Where the explosions happened
Post box outside The Reach, Smugglers Lane, Bosham
Post box at the entrance to Bosham Hoe
Post box on the A286 junction with St Nicholas Road, Lavant
Post box outside The Fox Goes Free pub, Charlton Road, Charlton
Post box near the Star and Garter pub, East Dean
Post box in Folly Lane, Barlavington
Telephone kiosk on the corner of Richmond Road, Westerton
Telephone kiosk at the High Street junction with Highfield Lane, Oving