Police have called for calm in the wake of the brutal murder of a Saudi Arabian student.
Nahid Almanea died after she was stabbed 16 times while walking along a path in Colchester, Essex, on Tuesday morning.
The 31-year-old had been taking an English language course at the University of Essex since January as part of her studies for a life sciences PhD.
A 52-year-old man arrested in connection with her death has now been “positively eliminated from inquiries”, Essex Police said, and was released on Thursday night.
There are fears the killing could be linked to the murder of James Attfield, a vulnerable man with brain damage, who died after being stabbed more than 100 times in a park in Colchester in March after detectives said there were “obvious similarities”.
Police are also investigating whether Ms Almanea may have been targeted because she was wearing a Muslim abaya robe and a multi-coloured hijab headscarf.
Officers said there are other possible motives but called for calm, saying they are aware of and investigating threats of revenge attacks made on social media.
Chief Inspector Richard Phillibrown, the town’s area commander, said: “I see this murder as an attack on the entire community of Colchester and I believe we will all pull together to respond to it.
“I am confident that the vast majority of people in this town will pay no attention to those trying to stir up trouble.”
Essex Chief Constable Stephen Kavanagh and the county’s police and crime commissioner, Nick Alston, issued a joint statement, saying it is not yet known if the latest killing was motivated by Ms Almenea’s religion.
They warned against jumping to conclusions, saying this would be “deeply unhelpful, wrong and dangerous”.
The force released CCTV footage taken from a local newsagent which showed Ms Almanea’s last movements.