I am keen to establish if there was anyone in the area who saw or heard anything suspicious yesterday evening.
I'm appealing for anyone who has any information no matter how small to please come forward and help us with our inquiry.
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Tencho Hristov ignored warnings and got trapped between barriers at Roydon in Essex.
The 6km bike track will include 130m of the South Circular near Kew Bridge.
The unfortunate officer was taken to a central London hospital for treatment and his condition is not life-threatening.