It seems you're looking for the full feature film Sethurama Iyer CBI (often referred to as the CBI series in Malayalam) with English subtitles.
Official channels like Saina Movies often upload high-definition versions of the older films with embedded English subtitles for international fans. Why Is Sethurama Iyer Still Relevant? sethurama iyer cbi with english subtitles full
You can find these films on various streaming platforms, though subtitle availability may vary by region: It seems you're looking for the full feature
The series is unique in Indian cinema for featuring the same lead actor, director, and writer across five films released over 34 years: Oru CBI Diary Kurippu (1988) You can find these films on various streaming
A direct sequel involving the mysterious death of an actress. Many fans consider this the tightest script of the franchise.
: The modern-day return of the legend. Why Fans Seek English Subtitles