And suppose further, that nobody witnessed this, and that one instant later, by some very unlikely process, some matter or energy spontaneously organized itself into an exact duplicate of you, down to every last quantum wobble, in exactly the same place that you were standing.
Would either this new you or the old you notice? Would "you" still be "you"?
And would it matter?
What if he recombines you, just like in your example an instant later. Is it murder?
A minute later. Murder?
An hour, day, week, month, year. Murder?
What if he just promises to everyone to put you back together. Later. In the future. Murder?
What if he didn't delay at all? Did he kill you just by letting your atoms get ripped apart and reassembled elsewhere?
Or is this whole continuity-of-self thing a sham?
It seems that people have their own definition of death with details added to the general concept. Then, when exposed to these hypothetical scenarios, they either say "it is murder" or "it isn't murder", depending on what their personal definition of "death" is.
The problem is that if we redefine death as "no chance of ever coming back", some people would still not be ok with being temporarily disintegrated because they believe it would be someone else who would come back.
So the concept of death should actually be split in two: death as in "I believe it would not be me anymore", and death as in "the functional unit defined as you would not be operational anymore".