A fifth man has been arrested in connection with last weekend's attack on a university student in Aberystwyth.
Ifan Richards Owens, 19, is in critical condition following the attack on High Street at around 2.20am in the early hours of Sunday, Janaury 14.
A 24-year-old man, arrested on suspicion of assault, has now been arrested and is in police custody.
Earlier this week, three men aged 20, 23 and 25 were released under investigation. A 19-year-old man has been released on police bail.
Enquiries are ongoing with an incident room in place at Aberystwyth Police Station.
DCI Anthony Evans said: "We are still trying to find the adult male who administered first aid to Ifan before emergency services arrived.
"We would really like to speak to him to see if he can help in any way with our investigation.
“Anyone else who has not yet come forward who was in the High Street area between 12.45am and 2.30am and has information or footage of the incident, please get in touch.
"What may seem insignificant to you could be a vital piece of the jigsaw in this investigation."
Anyone with information is urged to contact the incident room in Aberystwyth by calling 101 quoting incident 402 of Jan 14th.