I am searching it on Google but I am not finding,who had discovered static electric spark for the first time,that later Benjamin Franklin proved that this spark(already discovered spark) is same as that of the outside lighting? As I know scientists have seen attraction (charged amber and charged glass rod attraction) and repulsion(charged glass rod and charged glass rod repulsion) but no electric spark they have seen then from where did the scientist know about electric spark before Benjamin Franklin?
As comments suggest, the static spark is (like fire) found in nature - it was not discovered.
In terms of who first harnessed the static spark or created one purposefully, that is also likely to date to time immemorial, since commonly used textiles (like wool, especially) tend to create static easily.
The first experiments by "scientists" (a role that in the past was not a specific professional occupation, and would have been less clearly defined) with electric sparks probably began around the time of the invention of the chemical battery.
From my prospect von kliest, the discoverer of leyden jar,is the first scientist to know about spark.
As he might have seen when he took the charged glass rod near the
nail of the jar then the glass rod lost its charge as it can't attract any more and taking his finger towards the nail he could see the spark and feel the shock.