Police have issued images of club goers they believe are key witnesses to a crush which killed two women in a nightclub last year.
Northamptonshire Police said they have spoken to more than 1,000 people since the incident at the Lava & Ignite nightclub in Northampton last October, which led to the deaths of Nabila Nanfuka, 22, and Laurene-Danielle Jackson, 19.
They want to speak to 28 people who were caught up in the crush and captured on CCTV who have yet to come forward to help them complete their investigation.
A poster, which uses a photograph from inside the club showing the crush taking place on a staircase in the club, is being circulated to universities across the UK.
The poster includes the faces of 28 "key" witnesses who police hope will come forward with information to help them piece together a final picture of what caused the crush to happen.
CCTV clips from inside the club are also being released and circulated on Facebook and YouTube in a bid to identify people who were on the staircase immediately before and after the crush.
Some 1,500 people from across the country attended the Wickedest Wickedest event at the club last October. Many were university students who travelled to Northampton on organised coaches.
Launching a new appeal for information, Detective Inspector Louise Hemingway, from Northamptonshire Police, said: "We have spoken to over 1,000 witnesses and reviewed several hours of CCTV footage.
"In doing so it has become apparent that whilst we have a clear picture of what happened, there are a small number of key witnesses that we have yet to speak to who were in the immediate vicinity of where the two women were crushed.
"We need the help of the people in the CCTV and the poster to piece together what happened."