Yes this is true, but apparently he wasn't actually bludgeoned with anything although it was widely reported that he was. The current theory is chemical agents had something to do with it (like pepper or bear spray).
>According to one law enforcement official, medical examiners did not find signs that the officer sustained any blunt force trauma, so investigators believe that early reports that he was fatally struck by a fire extinguisher are not true.
https://www.cnn.com/2021/02/02/politics/brian-sicknick-charg...
>According to one law enforcement official, medical examiners did not find signs that the officer sustained any blunt force trauma, so investigators believe that early reports that he was fatally struck by a fire extinguisher are not true.