they weren't trying to kill anyone... you fucking liberals started this shit
They broke into Capitol Building with nooses, bombs, and disposable handcuffs. They were screaming, "hang Mike Pence!!!" They severely beat several Capitol Police Officers who delayed them for long enough to get the politicians to safety. One police officer, and one of the terrorists died from the storming of the Capitol Building.
The first and last part of that makes them guilty of murder. They broke into the Capitol Building, which could foreseeably cause deaths, so would be a prerequisite crime. And, there were two people dead as a result of that crime. The attempted murders are just the cherry on the top of the case.