Net found twisted round foot of body in river (4)
I believe the answer is:
tyne
'river' is the definition.
(river in the North East of England)
'net found twisted round foot of body' is the wordplay.
'found twisted' is an anagram indicator (a twisted or distorted version of the letters).
'round' means one lot of letters goes inside another.
'foot of' indicates one should take the final letters.
The final letter of 'body' is 'y'.
'net' anagrammed gives 'tne'.
'tne' going around 'y' is 'TYNE'.
'in' is the link.
(Other definitions for tyne that I've seen before include "River running through Newcastle" , "River of Northumberland" , "Northumbrian river" , "River of NE England" , "Flower" .)