Apple has been dealt a setback in its patent battle against Samsung, with officials retrospectively ruling that they should not have issued a key "pinch to zoom" patent to the Cupertino-based firm.
The US Patent and Trademark Office determination "rejects all claims" that Apple has to the '915 patent, which covers the use of a single finger to scroll through a page, as well as using two fingers to zoom in and out.
The decision was highlighted by Samsung in a filing with a California district court. The patent was one that the Korean company was previously found to have violated and contributed to the awarding of a $1.05 billion (£646.2m) judgment in Apple's favour. As a result, having that patent invalidated could benefit Samsung.
When asked if Apple proved that Samsung took action that it knew would result in infringement related to the '915 patent, the jury in the blockbuster trial said yes for all devices bar one.
As noted by the New York Times, however, Apple can appeal the PTO's decision, so the "pinch to zoom" patent is still technically in play.
In October, the USPTO also took issue with Apple's "bounce back" patent. Apple has appealed that decision as well.
Earlier this week, Judge Lucy Koh denied Samsung's request for a new trial based on juror misconduct accusations.
Judge Koh also rejected a request from Apple for a ban on certain Samsung products in the US.