Observer, I heard, distorted its news (10)
I believe the answer is:
eyewitness
'observer' is the definition.
(eyewitness is a kind of observer)
'i heard distorted its news' is the wordplay.
'heard' shows a homophone (sound like).
'distorted' indicates an anagram.
'i' is a homophone of 'eye'.
'its'+'news'='itsnews'
'itsnews' is an anagram of 'witness'.
'eye'+'witness'='EYEWITNESS'
(Other definitions for eyewitness that I've seen before include "evidence?" , "Onlooker" , "Spectator" , "The Observer" , "One seeing (eg, crime)" .)