A 40-year-man questioned about the disappearance of a Hertfordshire University student has been released under investigation.
The man was detained on suspicion of the murder of Joy Morgan, Hertfordshire Police said.
Morgan was last seen in Ilford, east London, on 26 December and was reported missing on 7 February. Tuesday was her 21st birthday.
She is black, of slim build, around 5ft 5in tall, with black afro-style hair which she often covers with a scarf.
She also wears glasses.
Her family have issued an appeal, saying: “We love you, we miss you.
“Wherever you are, text or call so that we know you are alright.
“It doesn’t matter what has happened, just come home.”
Morgan has links to Ilford, Battersea and Cricklewood in London, as well as Bedfordshire.
Welwyn Hatfield Chief Inspector Tannis Perks said: “This is a complex missing person investigation and we are working hard to establish the circumstances surrounding Joy’s disappearance.
“Understandably her family are extremely worried about her and are desperate to know that she is OK.
“I would like to appeal to Joy to get in touch to let us know that she is safe.”
He said anyone with information should call police on 101, or contact 999 with immediate sightings.