People chasing son trapped by model (5)
I believe the answer is:
posse
'people chasing' is the definition.
I can't judge whether this defines the answer.
'son trapped by model' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'trapped by' is an insertion indicator.
'model' becomes 'pose' (model can mean to pose).
's' placed into 'pose' is 'POSSE'.
Can you help me to learn more?
(Other definitions for posse that I've seen before include "Group temporarily established for some purpose" , "Sheriff's assistants" , "Sheriff's party" , "Group aiding lawman" , "Troop at the service of a local sheriff" .)