The cloak (dis)appears

Yesterday, Rome and Rei had conjectured that Rei's would-be killer most likely was one of the remaining Darwin members running loose on Deucado. They knew that the Darwin members were sent to Deucado in the specially fortified gray sarcophagi in the front of the Ark II. Rome asked Rei how many there were, so they could gauge what they were up against and... Well, I'll let Rei tell you:

     “I didn’t pay enough attention,” Rei said. “I think we need to go back and actually count.” Rei turned to MINIMCOM. “How many of the Darwin people did you and Junior cart off to Virga on Helome?”
     “84 the first trip. 20 the second,” MINIMCOM answered. “104 total.”
     “There,” Rei said. “So all we need to do is figure out how many we started with, subtract out 104 and what’s left is how many we’re looking for.”
     Rome smiled. “I do not think your ability to think has been much impaired. However, you forgot one person.”
     “Who?” Rei asked.
     “Captain Keller. No matter what the theoretical number, you must add one since he was one of the original 84 sent to Virga on Helome.”
     Rei sighed. “Yeah,” he said. “I don’t know if this helps or not but I know that some of the sarcophagi were damaged. I remember seeing them in the cave behind The Cathedral.”
     “Were they white or gray?” Rome asked.
     Rei put his hand up to his head and rubbed his forehead. “I don’t remember,” he said. “Dammit.”
     “It’s OK, Rei, we will check it out,” Rome said. She turned to MINIMCOM. “Would you mind taking us to Rei’s Ark and then to The Cathedral?” she asked. “We need to do our survey.”
     “Your safety and well being is my first and only concern at the moment,” answered the livetar. “I am at your service until this matter has been resolved.”
     “Then let us begin,” Rome said, rising.
     Together, the group left the house. What they did not see was that after they were gone, the front door opened, apparently all by itself, and then closed again.

Uh-oh. A door opening and closing by itself and a missing invisibility cloak. Those two things can't be a coincidence. But who are they are and how are they related? We will have to find this out as we go along.