How to delete multiple records
Below is the best way I know to delete multiple records using scripting. No need to put deleteMultiple() in a while loop, it will iterate over the records by itself.
var grCSS = new GlideRecord('incident');
grCSS.addQuery('sys_updated_by', 'adm-jesse.szepieniec'); // optional
grCSS.query();
grCSS.deleteMultiple();