Police have released a new video of missing university student Libby Squire, a month after she disappeared.
The last known sighting of Ms Squire was on February 1 shortly after midnight after a night out with friends.
The video released on Thursday shows the 21-year-old smiling and laughing with her friends at Hull University.
Ms Squire's mum, Lisa, said the video was "very Libby."
Detective Superintendent Martin Smalley, the Senior Investigating Officer leading the investigation, said efforts were continuing to find Ms Squire.
He said a man remains under investigation for kidnap in connection with her disappearance.
“We have always kept an open mind as to Libby’s disappearance, hopeful we would find her and be able to return her home safely to her devoted and loving family."
He added: “Throughout the entire investigation we have consulted with national experts from other forces and agencies as well as river and water specialists and search professionals, to ascertain where Libby may be and understand exactly what happened that night.
“Although we have followed up hundreds of leads and lines of enquiry and carried out intensive searches as part of the investigation over the last four weeks, as time passes by with no positive indication as to where Libby is or what has happened to her, Libby’s disappearance remains unexplained and we must increasingly consider she has come to harm."
Ms Squire's disappearance has sparked an intensive police search.
For weeks, 50 detectives and hundreds of uniformed officers have been working around the clock to find Miss Squire.
Mr Smalley said CCTV footage has formed a "crucial part" of the investigation so far as detectives work non-stop viewing hours of film to piece together Libby’s movements.
Last week, police released footage of four potential witnesses who may have vital information.
The footage showed four people on Oak Road close to the junction with Clough Road between 1.13am and 2.34am on the day Miss Squire was last seen in Hull.
Earlier footage released by police showed Miss Squire dressed in black and walking along the road outside The Welly club, in Beverley Road, Hull.
More CCTV footage showed a man getting in and out of a car, minutes after the last sighting of the philosophy student.
It was filmed by a camera on a lettings agency next door to the club and shows Miss Squire, who appears to be dressed in a black jacket and black skirt, stumble near barriers on the road as she walks towards the nightclub.
The investigation has seen specialist search teams, underwater officers, dog teams, neighbouring forces, search and rescue teams, fire officers, the coastguard, the police helicopter, local businesses and members of the public taking part in the search.
Officers have repeatedly scoured gardens, alleyways, waterways and a pond in an area around Miss Squire's home on Wellesley Avenue.
Ms Squire's mother said the past month has been one of "utter heartbreak."
”It's now been four weeks without our beautiful Libby. A month of utter heartbreak and despair," she said in a statement.
“As a family we are incomplete. We miss her more than we could ever say. We just want her back with us.
“Please if anyone has any information no matter how insignificant it may seem, contact the police."
