The characterization was that Sanders is "Saturnine" while Clinton is circling the wagons and counterattacking.
Clinton said that she was ready to move on from this, while Sanders is looking for an investigation.
Since there's nothing else to discover about the Sanders campaign, the public and repeated calls for investigation is presumably to find a smoking gun to prosecute the Clinton campaign, the DNC and the data company for collusion and worse.
Seems like a counter-attack to me.