Not NTRO, there was nothing Technical about TSD, it was HUMINT and black ops unit. NTRO is a SIGINT/ELINT/TECHINT unit similar to US's NSA. We as Indian might like to think that TSD's role is played by the 'Unknown gunmen' but na we have no such capability now. The 'Unknown gunmen' were known to be blue on blue
Also let's see this:
In mid-80s, we had CIT-J & CIT-X doing these sorts of works
That got closed
We had TSD in the aftermath of 26/11
That got closed
We have no idea what agencies work in this domain now, probably we'll only know about their name if and when they get disbanded also. So I wish we never do
(Also, technically the TSD is still there, there's no one to man it or take care of it. On paper it's there (ironic cause on paper the unit did not even exist) but you know what I mean....all this was said by Col Hunny Bakshi himself.