For me, this phrase is indelibly associated with my childhood and the soap, Crossroads, and a character called Arthur Brownlow. Arthur was investigated by the police for something at one point and “helping police with their enquires”.
I asked my dad what it meant, expecting all wisdom to rest there.
“It means he did it”, he replied.
I guess my legal career was then inevitable.
The last I recall of Arthur Brownlow was the look of surprise on his face as he bounced off the windscreen of the hit and run car that brought his Crossroads career to a premature end.