Clients, witnesses, stoolies. Er, sources.
I’m going to go with Peter Gunn. He “knows people” in the under world. Fromer convicts, con men, under world infomants. Their name is legion, and they get killed like swatted flies, along with many of his clients or their relatives. Even his side kick, Lt. Jacobi, chides him, “Pete, you’re getting people killed.”
Which private eye would you say got the most innocents killed?
Footnote: No one in Peter Gunn is innocent, but hey.
I haven’t seen an episode of Mannix in almost fifty years, but I seem to remember a lot of people getting killed on his watch. I suppose these were witnesses and stoolies. I don’t think he ever lost a client, especially if she was a hot babe.
Do comedies count? If so, the title character nuked a whole city once in Sledge Hammer!
If not, yeah, I’ll have to go with Peter Gunn, too.
I’ll see what I can do.
Frank Drebin killed five actors at a Shakespeare-in-the-Park production of Julius Caesar. Good ones!
In the old TV show The Untouchables Eliot Ness could be close to the top. I remember reading the entry on the book “Cult TV” -paraphrasing from memory- :
How many times a guy decided to denounce a gangster and Eliot Ness or another investigator when arriving to talk to the informant, the informant drops dead or that he was already murdered by the mafia?
[Narrator]Stay tuned for the next pigeon![/N] 
Does Jack Bauer count as a “detective”? 'Cause considering that at least two nuclear strikes on US soil happened on his watch, he’s gotta have a body count in the tens of thousands at a minimum.
The odd thing about The Untouchables , which was heavily criticized for being “so violent,” is that we never saw any bullets actually hit somebody, or any blood/guts/brains being spilled.
There was one episode in which Phillip Pine (the evil “Colonel Green” on ST: TOS ) got hit by a guy wielding a Tommy gun. The wall behind him exploded in a line of squibs, but there were absolutely no signs of trauma on his body.
In another, Stanley Adams (trader “Cyrano Jones” on ST: TOS ) was whacked while he was sitting in the back seat of a roadster, but it was obvious the guy who pulled the trigger wasn’t even aiming at him.
And so on and so forth.
When I see five guys in togas stabbing an unarmed man in a public park, I shoot the bastards. That’s my policy.
It happens all the time on NYPD Blue. The reluctant witness turns up dead at the end of the episode or the next one. Informants usually last a few episodes- long enough to build up a little drama around their deaths. The informants are usually not purely “good guys,” though, and are at least junkies who keep going on about wanting to be paid for their info.
On the other hand, they don’t tend to get into a lot of shootouts and explosions with high body counts among unnamed extras. Still, though, I would think after the first few times the reluctant witness very much did get killed exactly as they had feared, they wouldn’t be so quick to be all “Just give us a name! We can keep you safe!” and act like the reluctant witness was being completely unreasonable.
Anybody ever notice how often Magnum got the shit kicked out him?
In no way an answer to the question. Sorry.
I can’t remember for sure, but I think being an acquaintance of Sonny Crocket was bad for ones long term health.
Even his wife got whacked.
And Zito.
That is quite ok, Gatopescado. (Catfish?) Selleck played a “perfect” PI on a Rockford episode. He had a pistol in his glove box that opened easily for him, but stuck for Rockford. Selleck got the reward in a case they both worked on, and gave it to an orphanage, while Rockford was hoping to be able to eat somewhere other than Burger King. Give him hell, I say!
Now Rockford seemed to get beaten up once an episode (and sometimes twice). His poor kidneys. I don’t know how many deaths he was responsible for, but it was notable how many times he was found kneeling next to a recently deceased person, often while holding the gun that had done it (never touch the gun, Rockford, never touch the gun!)
He had a pardon, but wasn’t supposed to have a gun, that’s why he kept it in a ccokie jar.
Picking up the gun that shot someone has gotten many a TV PI in trouble.
James Garner had a bad knee, from football or Korea, but in one episode he was limping so obviously the writers had him get shot in the leg to explain the limp.
“His gun is deadly. Mine’s in the cookie jar.”
My old Pappy used to say that.