Missing University of Hull student Libby Squire is pictured in Paris in May 2017 during a gap year when she visited with friends The parents of missing Hull student Libby Squire have spoken of the 'unending torture' they have suffered since she disappeared three weeks ago. The 21-year-old was reported missing after going on a night out with friends, and was last seen at around 12.05am on February 1. Humberside Police have previously conceded that Miss Squire 'may have come to some harm'. In a statement released through the force, the student's parents, Lisa and Russ Squire, said: 'It's been three weeks now since our beautiful girl was last seen. 'In that time we haven't been able to speak to her, and we haven't been able to hug her. 'We haven't been able to tell her we love her, or hear that she loves us. 'She went out to have fun with her beloved friends. 'Since then it has been a time of unending torture for her friends and family but we all have unending hope that she will be found. 'We send love and thanks to everybody for their support over these past weeks. 'Please, please if you have any information contact the police and pass on any information that you can.' On Tuesday, Humberside Police released CCTV footage showing four potential witnesses who may be able to shed light on Miss Squire's mysterious disappearance. The clips shows a cyclist, a pedestrian and a pair walking together in Oak Road between 1.13am and 2.34am on the day Libby disappeared. Detective Superintendent Martin Smalley said: 'These four people are potentially witnesses who we need to identify and speak to as part of the investigation. Libby Squire's parents said they still have 'unending hope' that their daughter will be found One of the people featured in Humberside Police's CCTV footage of four witnesses, who they believe 'may have seen or heard something that could be vital' The four people who feature in the CCTV footage from February 1 in Hull are circled above A map shows the student's movements on the night of January 31 in Hull before she vanished 'While the footage isn't clear enough for anyone to recognise who they may be, the four people in the clips will know if they were in that area at the times given.' A force spokesman said that, although several calls have been received, the witnesses have not yet been identified. Police search Oak Road playing fields in Hull last Tuesday as part of their investigation The CCTV footage shows four people on Oak Road near the junction with Clough Road This graphic shows where Miss Squire was last seen in relation to where the CCTV was taken Timeline: The hunt for missing Libby Squire 11pm, January 31: Libby is refused entry at Welly Club around two miles from her home and put into a taxi 11.30pm: Libby was dropped off on Wellesley Avenue - but does not go inside her house 11.45pm: Libby was seen sitting on a bench around the corner on Beverley Road. A witness says she was seen speaking to the driver of a car. 12.09am: Detectives believe Libby stayed in the area for about half an hour - but is then gone. 12.30am, February 1: A near-neighbour says she woke up after hearing 'blood-curdling' screams. February 6: Pawel Relowicz is arrested on suspicion of Libby's abduction February 8: Police ask for more time to interview abduction suspect. February 10: Relowicz is charged with voyeurism, burglary and indecency - but no charges related to Libby's disappearance. February 11: He pleads not guilty. Miss Squire was last seen at the junction of Beverley Road and Haworth Street in Hull at around 12.05am on February 1 wearing a Top Shop black denim skirt and faux leather jacket and distinctive trainers. Earlier that evening she was refused entry to a nightclub as she was too drunk. A taxi dropped her off near her house but she walked up the road to sit on a bench instead of going in. Her mother Lisa Squire and friends helped police identify the clothes which in turn helped police to try and spot the student on hundreds of hours of CCTV they have analysed. Five days later, Pawel Relowicz, of Raglan Street, Hull, was arrested and questioned on suspicion of abduction. He appeared before magistrates charged with a number of offences unrelated to Miss Squire's disappearance, which police said he remains under investigation for. So far police have searched properties, gardens, playing fields, gardens, waterways and a pond near Miss Squire's home and the operation continues. Libby Squire was a second-year philosophy and religion student at Hull University. She was described earlier as a 'kind, thoughtful, beautiful' girl by her parents speaking at a press conference after she disappeared. Police arrive to search Oak Road playing fields in Hull last Tuesday over the disappearance The Oak Road playing fields have become a focal point in the search for student Miss Squire Her parents Lisa and Russ Squire (pictured on February 4) are desperate for her safe return Clothes similar to the ones worn by Miss Squire on the night the student disappeared in Hull All rights reserved for this news site dailymail and under his responsibility