You can, but it's VERY challenging.
In one case a leg was found and the defense attorney successfully argued that since a man can live without a leg, finding a leg was no proof of his death!
And if you try and fail, and the accused is acquitted, they cannot be charged again under double jeopardy when a body finally turns up.
Most grand juries will no bill a case without a body.
How did I know that?
I was replying to an absolute no body no trial.
It may be hard to do but but it can happen because it has happened.