Four men have been taken to hospital with stab wounds following an incident at a pub in Stevenage on Saturday night (September 17).
Police were called to St Nicholas Tavern in Canterbury Way at 10.50pm to reports of a stabbing.
Four had been stabbed and were taken to hospital for treatment.
The pub and surrounding shops and car park area was cordoned off for much of Sunday, September 18.
Enquiries are ongoing and officers are appealing for anyone with any information to contact them.
You can report information online at herts.police.uk/report, speak to an operator via online web chat at herts.police.uk/contact or call the non-emergency number 101, quoting ISR 903 of 17 September.
Alternatively, you can stay anonymous by contacting Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.