But why should he have personated his brother?
He could not have already committed the murder.

There had not been time enough.

He would have had to leave Woodford before John Bellingham had set out from Charing Cross.
And even if he had committed the murder, he would have had no object in raising this commotion.

His cue would have been to remain quiet and know nothing.

The probabilities were all against the personator being Godfrey Bellingham.
"Then could it be Mr.Jellicoe?
The answer to this question is contained in the answer to the further question: What could have been the object of the personation?
"What motive could this unknown person have had in appearing, announcing himself as John Bellingham, and forthwith vanishing?
There could only have been one motive: that, namely, of fixing the date of John Bellingham's disappearance--of furnishing a definite moment at which he was last seen alive.
"But who was likely to have had such a motive?
Let us see.
"I said just now that if Mr.Jellicoe had murdered John Bellingham and disposed of the body in the mummy-case, he would have been absolutely safe for the time being.