How real is the threat of murderers being gunned down

We watch a lot of crime shows and invariably when murderers are transferred somewhere they are nattily attired in a bullet proof jacket. Example: Chardon High School shooting: THIRD classmate dies as TJ Lane's online rantings are revealed | Daily Mail Online

Is there a real threat of them getting shot? Oswald aside, has it ever happened? Is the Oswald incident where it started?

It wasn’t a murderer, but in 1984, Gary Plauche killed Jeff Doucet while Doucet was being transferred from California to Baton Rouge for trial. Doucet had sexually abused and kidnapped Plauche’s son (who was recovered unharmed). Plauche was tipped off to the time and date of the transfer by a television station employee. Plauche waited in the airport, and when police came by with Doucet, Plauche shot Doucet in the side of the head.

I remember seeing the news report at the time, and remembered just enough that I was able to find the details via google.

Plauche was given a seven-year suspended sentence with five years’ probation and 300 hours of community service. He did not serve any time in jail.

Larry Flint was shot near the courthouse on his way to trial. There is definitely a risk to people accused of certain crimes. When in police custody, the government has a duty to protect them, thus the vests.

the mob will kill people (or try to kill them) who might testify against them. But that is not when the person is in police custody from what I recall. It has happened when the person was out on bail.

Wait, Plauche’s son was kidnapped and sexually abused and you say he was recovered unharmed? We may have a different definition of “harm.”

Yeah, I thought the same thing. I’m guessing he meant still alive.

Yeah, unharmed in this case means alive and no bullet wounds, knife wounds, broken bones, etc.

Doucet had been sexually abusing Plauche’s son for over a year, so obviously you have all of the psychological and physical trauma associated with that.