iel--if you will,
please."

Mike stood up as the captain sat down. "The question that has bothered
me from the beginning has been: Exactly what killed Lieutenant Mellon?
Well, we know now. We know what killed him and why he died.

"He was murdered. Deliberately, and in cold blood."

That froze everybody at the table.

"It was done by a slow-acting but nonetheless deadly drug that took time
to act, but did its job very well.

"There were several other puzzling things that happened that night.
Snookums began behaving irrationally. It is the height of coincidence
that a robot and a human being should both become insane at almost the
same time; therefore we have to look for a common cause."

Lieutenant Commander von Liegnitz raised a tentative hand, and Mike
said: "Go ahead."

"I was under the impression that the robot went mad because Mellon had
filled him full of theological nonsense. It would take a madman to do
anything like that to a fine machine--therefore I see no peculiar
coincidence."

"That's exactly what the killer wanted us to think," Mike said. "But it
wasn't Mellon that fed Snookums theology. Mellon was a devout churchman;
his record shows that. He would never have tried to convert a machine to
Christianity. Nor would he have tried to ruin an expensive machine.

"How do I know that someone else was involved?"

He looked at the giant Lieutenant Keku. "Do you remember when we took
Mellon to his quarters after he tried to brain von Liegnitz? We found
half a bottle of wine. That disappeared during the night--because it was
loaded with Lysodine, and the killer didn't want it analyzed.

"But, more important, as far as Snookums is concerned, is that I looked
over the books on Mellon's desk that night. There weren't many, and I
knew which ones they were. When Captain Quill and I checked Mellon's
books after his death, someone had returned his copy of _The Christian
Religion and Symbolic Logic_. It had not been there the night before."

"Mike," said Pete Jeffers, "why would anybody here want to kill Lew
thataway? What would anybody have against him?"

"That's the sad part about it, Pete. Our murderer didn't even have
anything against Mellon. He wanted--and _still_ wants--to kill _me_."

"I don't quite follow," Jeffers said.

"I'll give it to you piece by piece. The killer wanted no mystery
connected with my death. There are reasons for that, which I'll come to
in a moment. He had to put the blame on s