A robber was stopped by locals after a "horrific attack" where a crow bar was used at a small Anglesey post office.
While one man fled with cash from the till, his accomplice was detained by customers in Rhosybol, near Amlwch, on Monday.
Police have appealed for witnesses to the incident that happened at about 17:15 GMT.
Supt Nigel Harrison said staff were left traumatised and with minor injuries.
He added: "This was a horrific attack on a small post office in a close knit community and I'm not surprised local people stepped up to protect their community."