More than 30 family members, friends and members of the public joined a search during Saturday afternoon to find missing Michael Brookes.
The 19-year-old from Preston was last seen leaving Avenham Park at around 2am on Sunday (14 January).
A statement released by his family said; “Just on our way home after spending the afternoon searching for our Michael, unfortunately we are no wiser as to where he is. Michael’s Mum and other family members are out searching throughout the evening.
“We would like to thank you all who took your time to search today, we are all overwhelmed by the love and support shown, we are truly grateful. If you are still out and about, please stay safe and take care.
“If anyone has any information no matter how small please phone the police.”
They have also released two new pictures of Michael – one above and the other is below.
Since Michael’s disappearance a search, led by Preston Police, has seen marine units out on the River Ribble, the police helicopter called in and a number of other organisations involved.
A search – one week on from Michael’s disappearance – is planned for Avenham Park again from 1pm on Sunday (21 January). The meeting point is by the flag pole.
Michael’s family have also released a poster, available to download below, which can be put up in the search for Michael.
Inspector Patrick Worden said: “Michael has been missing for a number of days now and we are very concerned for his welfare.
“Officers, with the support of specialist teams from the region, have conducted searches across the area Michael was last seen and we remain hopeful of finding him.
“If you saw him, or know where he is, please contact us immediately.
“Any information, no matter how small or seemingly insignificant, could prove crucial to our investigation.
“Furthermore, I would urge Michael, if he sees this appeal, to call us to let us know he is safe and well.”
Anyone with information can contact police on 101 quoting log reference 0641 of January 14.