Detectives investigating the "brutal" murder of a Saudi Arabian student in Colchester are questioning a 19-year-old man.
Nahid Almanea 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.
Essex Police said the man was held shortly after midnight in connection with a separate assault.
His arrest followed a report from a female jogger that a man had approached her and tried to grab her near Peache Road, Colchester at around 10pm, on June 19.
She was able to fight him off and make her way home - where she immediately contacted police.
A police spokesman said: "Following further enquiries he was then further arrested shortly after 4pm today in connection with the murder investigation.
Police have been patrolling a large area in Colchester "He remains in custody for questioning."
Earlier, investigators promised to "unrelentingly" pursue all lines of inquiry in the hunt for the student's killer.
Police were investigating whether Ms Almanea's clothing - an abaya robe and hijab headscarf - was a factor in the stabbing, but stressed they did not know for sure.
They said there were other possible motives and called for calm as they confirmed they were investigating threats of revenge attacks made on social media.
Officers warned local people not to go out alone and to be vigilant.
They said the fact that she was stabbed multiple times bore "obvious similarities" to the murder of James Attfield, a vulnerable man with brain damage.
He was stabbed more than 100 times in a park in Colchester in March, but Essex Police have stressed the cases remain separate investigations.
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