"拼图辨认嫌疑犯" can be translated into English as "identifying suspects through a jigsaw puzzle (method)" or more naturally as "identifying suspects by piecing together clues (like a jigsaw puzzle)".
The first translation directly references the "jigsaw puzzle" as a method, while the second emphasizes the act of piecing together clues, which is the essence of the puzzle-solving process in this context. Both are acceptable, but the second might be more fluid in everyday English usage, as it focuses on the action rather than the object (puzzle) itself.
For a more concise and contextually appropriate expression, you could also say:
"Piecing together clues to identify suspects"
"Identifying suspects by assembling evidence (like a jigsaw puzzle)"
The choice depends on the specific nuance you want to convey.