Catches second criminal near back of buildings (6)
I believe the answer is:
snares
'catches' is the definition.
(snaring is a kind of catching)
'second criminal near back of buildings' is the wordplay.
'second' becomes 's' (common abbreviation).
'criminal' indicates anagramming the letters.
'back of' suggests the final letters.
The last letter of 'buildings' is 's'.
'near'+'s'='nears'
'nears' anagrammed gives 'nares'.
's'+'nares'='SNARES'
(Other definitions for snares that I've seen before include "Game traps" , "Traps for catching birds or animals" , "hidden dangers" , "Traps set by Nasser" , "Traps, enmeshes" .)