And, in the history of courts, how many folks have gone to jail on the basis of circumstantial evidence? Coincidence, with strong motive, can be powerful in the jury's eyes.
Lots, but were talking about a modern case. And in almost all cases, to proceed with a murder trial as a prosecutor, you have to start with a coroner's report that has a cause of death attributable to human action/suspicious.
For example, there are all kinds of physical signs that can occur due to natural, non-criminal causes, but also may be evidence of murder. There was a case of an elderly hillbilly (for lack of a better term) who went to jail for killing his brother. Lots of evidence suggested intentional suffocation, but it was later revealed during his appeals process that the deceased suffered from a series of afflictions that would leave the exact same signs. The conviction was overturned. But the starting process was a declaration that the death was suspicious.
There are many toxins that can mimic natural causes of death, something many poisoners depend on. But there are tests that can be done that can, in many but not all- cases that can distinguish between natural and unnatural causes.
But in each case above, the is a determination that the death in question was at least suspicious, and a proven possible method of homicide.
Here, we have a head being crushed/collapsing in synch with someone making a gesture. In order to sustain a conviction, the prosecution would have to prove to the court that such a gesture could cause death. This is not trivial- most American jurisdictions have "junk science" laws dictating a standard of proof for putting forth scientific evidence. And unless you can show some peer reviewed documentation, or current experiments that are capable of being replicated by other scientists, you simply won't be able to sustain a conviction, because your theory of the crime will not even be allowed to be presented in court.