If a technology exists that allows the government to kill people with zero evidence left behind, there is nothing to be done. There is nothing that you can do, because, well, there is no evidence. Every death of every person would be a possible assassination and also possibly a natural death. It would be impossible to know even if the technology was being used.
I presume you have a method for proving something for which there is, by definition, absolutely no evidence?
There is always evidence, if the person who pulled the trigger is still alive.
And there is always the timing of the event to tip people off that it warrants further investigation. That is, unless there are people saying the idea is so absurd that it can’t be a serious issue.
Breitbart keeling over dead less than 5 hours after speaking to Arpaio and affirming that Arpaio’s evidence was good - and less than 12 hours before Arpaio was going to have a press conference announcing that evidence to the world (especially on an issue where the Soros operatives had already threatened almost the entire media with FCC/FEC annihilation and/or death or bodily injury to themselves and their families if they reported on it)... is suspicious. And especially when it happened the same day that Rush Limbaugh (the other somewhat-independent media voice) received out of the blue a package referring to 2 famous assassinations. AND when there are major discrepancies in the stories of Breitbart’s health...
It is made even more suspicious when it is followed up by the arsenic poisoning of a technician in the coroner’s office days before Bretbart’s autopsy was supposed to come out - and though the poisoning was done blatantly enough to be recognized by the coronor and was thus blatant enough for the perpetrator of the poisoning to be found, the LAPD wouldn’t investigate and instead told lies about what the doctors had claimed, in an attempt to make it look like it was just a friendly little heart attack that Cormier had.
The vigilance of the people makes a difference. The sleep and apathy of the people also makes a difference. Those who say, “It couldn’t happen here” or “Only crazy conspiracists would take this seriously” are literally a national security risk.
The evidence itself will tend to either confirm the suspicious nature of a death, or not. The people who don’t want the evidence sorted out and call people crazy if they are willing to look at the evidence are dangerous.