A pub goer was attacked with a baseball bat.
Two men entered the White Horse pub in Southminster at around 9.20pm on February 20.
One of them had then approached a 57-year-old man who was sat at the bar and hit him with the bat a number of times.
The victim fell to the floor and suffered rib injuries and cuts and bruising to his head, which needed hospital treatment.
The men involved then left the premises.
A 52-year-old man was arrested on suspicion of assault on Friday February 21 and taken to Chelmsford Police Station for interview.
He has been released on police bail pending further enquiries.
PC Tom Hurrell, of Chelmsford Police Station, said: "I would very much like to hear from anyone with information about this attack.
"We have arrested one man in connection with our investigations but I still need further information about the second suspect.
"There were a number of people in the pub drinking at the time that this happened and I’m sure some of them must have seen what happened or will have heard something about this attack.
"This victim was sitting at the bar minding his own business and the motive for the assault is still unknown.”
Anyone with information about the assault can call PC Hurrell at Chelmsford Police Station on 101 or ring Crimestoppers anonymously on 0800 555 111.