Wasn't he the doctor at the hospital? Enjoyed the programme but found the final episode a bit of a disappointment, to be honest. But, as has been said, it was a well made, well acted drama and, now that the DI has been put back on normal duties, I wouldn't be suprised to see the team back in further adventures.
In the real Ripper case one of the suspects, Mongague Druitt, drowned himself in the Thames.