Hear about a bearer (4)
I believe the answer is:
tray
'bearer' is the definition.
(I've seen this before)
'hear about a' is the wordplay.
'hear' becomes 'try' (to hear or try a case in the legal sense).
'about' indicates putting letters inside.
'try' going around 'a' is 'TRAY'.
(Other definitions for tray that I've seen before include "Carrier (for eg, crockery, food)" , "Informal meal" , "Kitchen carrier" , "Flat plate for carrying things" , "food container" .)