“This stuff suffocated Cong,” Lowen said.

“Right,” Wilson said. “As for the receiver, well, SmartBlood takes direction from its owner’s BrainPal via an encrypted channel and reverts by default to its primary role, which is oxygen transport.” He pointed to Abumwe’s PDA. “This stuff also communicates by encrypted signal. Its default state is off, however. It’s only on the job when it’s receiving a signal. Its signal doesn’t come from a BrainPal, however.”

“Where does it come from?” Meyer asked.

Lowen held up an object. It was Meyer’s white noise generator.

“It can’t be,” Meyer said.

“It can be,” Wilson said. “And it is, because we checked it. How do you think we can describe what this stuff does? This is why I said the interesting question is when this stuff got into Liu’s blood. Because this”—Wilson pointed to the white noise generator, which Lowen now set on the table—“strongly suggests that it happened before you folks left Earth.”

“How did you find it?” Abumwe asked.

“We walked through Liu’s death,” Stone said. “We knew when he died, and we knew that these ’bots needed a transmitter, and Mr. Bourkou said that he had been running the white noise generator to drown out Liu’s snoring.”

“You can’t think I did it,” Bourkou said.

“You set this thing off in the same room,” Wilson said.

“It’s not even mine,” Bourkou said. “Franz let me borrow it. It’s his.”

“That’s true,” Wilson said, turning to Meyer.

Meyer looked shocked. “I didn’t kill Cong! And this doesn’t make logical sense in any event. Cong was supposed to have a berth to himself. This thing wasn’t supposed to have been in the same room.”

“A very good point,” Wilson said. “Which is why I checked the effective transmitting radius of the generator’s ’bot transmitter. It’s about twenty meters. Your berth is right next door, and the berths are narrow enough that Liu’s bunk is well within the radius, even accounting for signal attenuation through the common bulkhead.”

“We’d been traveling for more than a week before we arrived here,” Meyer said. “Before this we had individual staterooms, but we were still close enough for this thing to work. I used it every night. Nothing happened to Cong.”

“Interestingly, there are two transmitters in the white noise generator,” Wilson said. “One of them affects the ’bots. The second affects the first transmitter. It turns it on or off.”

“So it wouldn’t have done anything until you got here,” Lowen said.

“This is crazy,” Meyer said. “I don’t have a remote control for this thing! Go to my berth! Check for yourself!”

Wilson looked over at Captain Coloma. “I’ll have crew go through his berth,” she said.

“Have you dumped trash recently?” Wilson said.