A Watford man was attacked from behind using a metal wrench, and had his ear bitten, during a fight near St Albans.
Police are appealing for two people who they believe may have witnessed the assault, which took place in Frogmore at 6.30pm on July 18.
A 28-year-old man from Watford was hit in the back with a long tyre iron and had his ear bitten.
It is believed that a man and a woman saw part or all of the incident and tried to intervene, having walk from the security gates of Frogmore Home Park.
The intervention allowed the victim to get away from the other man.
DC Rebecca Primrose, from the local crime unit in St Albans, said: “Despite making inquiries we have so far been unable to speak to them.
“They may have information that is vital to our investigation.”
A 37-year-old man from Croxley Green has been arrested on suspicion of assault occasioning GBH and has been released on police bail while investigations continue.
Anyone with information about the incident can contact police on 101 quoting crime reference F3/12/1149, or through Crimestoppers, anonymously on 0800 555 111.
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