Essex Police say they cannot yet be sure whether Saudi Arabian student Nadid Almanea was killed because she was wearing Muslim dress. It is one line of inquiry, they say.
Nahid's body was found on a footpath in Colchester on Saturday. She had been stabbed 16 times.
Speaking at a press conference today, Essex Police also said they were investigating whether her death was linked to another fatal Colchester stabbing in March.
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The man was taken early this morning to a south London police station where he remains in custody.
The Chancellor faces tough talks to build a Government while also dealing with the challenge from a resurgent far right.
Watch John McDonnell's speech at Labour Party conference 2017 live as he speaks to Brighton the audience from 12.15pm.