Penniless criminals finally caught (8)
I believe the answer is:
strapped
'penniless' is the definition.
(informal term for being short of money)
'criminals finally caught' is the wordplay.
'finally' says to take the final letters.
'caught' becomes 'trapped' (trapping is a kind of catching).
The final letter of 'criminals' is 's'.
's'+'trapped'='STRAPPED'
(Other definitions for strapped that I've seen before include "- - for cash (hard up)" , "not generating enough cash?" , "Without, or very short of, money" , "in need of money" , "Bound" .)