Appeals to help find the missing student Libby Squire have been shown on digital screens in Hull city centre, as officers investigating her disappearance more than a week ago were given more time to question a 24-year-old man arrested on suspicion of abduction.

The 21-year-old student was reported missing nine days ago in the early hours of Friday 1 February, having last been seen after a night out near the University of Hull, where she studies philosophy.

An intensive sustained search has since been mounted by police and volunteers, with officers scouring the gardens and alleyways in the area around Squire’s home on Saturday.

Sharing a picture of a large screen featuring Squire’s face, Humberside police tweeted:

If you're out shopping today in Hull city centre today you'll see these. You know we've been out searching for Libby Squire every day for the last week and thanks for your help. We have all come together. Thanks for letting us do our jobs as well #HelpFindLibby pic.twitter.com/lJyL2R6kXh — Humberside Police (@Humberbeat) February 9, 2019

Police are believed to be examining CCTV footage, which appeared to show a man getting in and out of a car minutes after the last sighting of Squire, close to where she is thought to have disappeared, according to ITV News, which said the clip is “a central part” of the investigation.

Det Supt Matt Hutchinson has appealed to the media and public to refrain from speculation about the name of the suspect arrested in relation to the search.

“This is a live investigation with multiple active lines of inquiry and any speculation as to the names of suspects or details of the case could seriously harm the investigation and our ability to find Libby,” he said.

The University of Hull student has not been seen since vanishing in the early hours of Friday 1 February. Photograph: Humberside Police/PA

Police were granted a further 36 hours’ detention on Friday to question the man, who was arrested on Wednesday night at an address about half a mile from Squire’s home, and then late on Saturday said they had been granted a further extension, until 9pm on Sunday.

Officers have said Squire was dropped off in a taxi near her home on Wellesley Avenue at 11.29pm on Thursday 31 January and was seen 10 minutes later on CCTV near a bench on Beverley Road less than a mile away, where a motorist stopped to offer help. Neither the taxi driver nor the motorist are suspected of playing any role in her apparent abduction.

A JustGiving page set up to help Squire’s parents has raised more than £3,000. Craig Hopkins, who set up the fundraising page, wrote: “Libby’s parents obviously have a tremendous amount to deal with at this time and the last additional problem they need is any financial concerns, especially as their daughter is a student in Hull, which is a considerable distance from the family home in Buckinghamshire.

“Even if you can only spare a few pounds, please do so, as all money raised will be sent to Libby’s parents to assist them financially at this emotionally challenging time.”

Squire’s parents, Lisa and Russ, from High Wycombe, Buckinghamshire, issued a statement earlier this week, saying “We just want [Libby] home,” and thanked people for their support in the large-scale search to find their daughter.

A police van carrying an 11 sq metre digital screen has circulated the area where Squire was last seen, with shops, takeaways, off-licences, pubs and bars asked to share any information and inform customers about the appeal. The KCOM stadium in Hull also displayed the appeal around the grounds during the Hull FC v Castleford Tigers RLFC match this week.

In a statement released on Friday afternoon, Humberside police said that the force is “still very much treating her disappearance as a missing person’s inquiry”.

A spokesman also thanked more than 50 volunteers who helped officers searching on Thursday night, when almost 2,000 flyers printed in English, Arabic, Russian, Lithuanian and Polish were handed out. Social media users were encouraged to share the appeal online using the hashtag #HelpFindLibby.