"This case is no longer in your jurisdiction, Detective Park. Frankly, I don't trust you anywhere near the crime scene."

Rather than meet Noelle's glare, Agent Charity Singh directed the forensic medical examiner to finalize his inspection of the body. The obvious signs were easy to read: the single bullet hole, the bruises suggestive of a struggle. Rigor mortis had yet to set in, so the timing, at least, was consistent with Maria's account. Only an autopsy would reveal the finer details.

The examiner covered the body's still-flaccid hands with plastic bags and rubber-banded them to protect any traces lodged under the fingernails, then slipped another another plastic protector over the scalp. To Noelle and Maria, it resembled a grotesque shower cap.

Into a zippered bag and onto a gurney went Johann Palmstroem. Although Agent Singh had spoken to him many times about the Park disappearance, and even grown to like the eccentric recluse, her expression was now stony, as if she were supervising the loading of airport baggage.

Her actions, however, were more telling.

Agent Singh had risen through the ranks at the field office, and though the stress lines now creased her face, seniority had its privileges. Despite the lateness of the hour, she had ordered a team to work overtime processing evidence. Thanks to her unusual position and a major injection of funding, staff, and technology, she could obtain preliminary forensic results in hours -- a turnaround that most law enforcement agencies would find inconceivable.

Singh's behavior made it clear that she had no intention of leaving Saturn Technologies for the night, nor of allowing Maria to leave, until she had found answers. Had Noelle known that this haste was driven by Henry Stein's imminent execution, she might have mustered a little sympathy. As it was, any trust Noelle held for the feds had long ago evaporated. To her mind, they simply wanted to pin the guilt on the first convenient suspect.

That suspect was Maria, who trailed Noelle and Singh helplessly. She hadn't been handcuffed yet, but it could only be a matter of time.

"Do you honestly expect me to just roll over for this?" said Noelle, following the team into the lobby.

Felicity Crowe was still there, slouched in a chair and checking her social media on her phone. She looked guiltily at Maria. Maria, in turn, looked back over her shoulder and flashed her partner a shaky smile.

"The victim was a federal contractor, or at least used to be. His work was deemed mission-critical," said Singh, who hadn't appeared to notice the exchange of looks. She spoke with big, round vowels and emphatic, sharp consonants, as if she expected to be misheard. "We could detain your sister indefinitely, with or without trial. So... yes. Rolling over is exactly what I expect you to do."

Noelle took an angry step towards the agent, but stopped short when Maria grabbed her elbow from behind.

"Stop. It won't help."

Her eyes pleaded: Don't make this worse. Singh pretended not to notice what was happening behind her as she methodically filled out a form authorizing transfer of the body.

"Am I supposed to just leave you like this?" asked Noelle.

"Maybe... you could try to get Mr. Fell when his flight lands?" said Maria. "I mean, I'll need a lawyer. Right?"

Agent Singh's pen stopped for a moment at the mention of Malcolm Fell. If the girl chose him of all people, it would be an awkward reunion. But she said nothing.

"All right," said Noelle. "But don't say too much. If they can twist your words, they will. You're being treated as the sole suspect here, at least for now."

Maria nodded. "I'll call you as soon as I can," she said, putting on a passable attempt at a brave face. And although this was unlikely to fool Noelle, Maria found that sometimes when she made a superficial show of courage, a little jolt of genuine determination followed. "I'm thinking it over," she said. "There has to be an answer."

She could not read the expression that passed across her older sister's face: a smile that didn't reach her eyes. "I'm sure there is. But don't feel like you have to figure it all out yourself," said Noelle.

"Okay," said Maria. It was a small word, the visible tip of a massive iceberg of subsurface emotion.

With a final hug, Noelle departed into the balmy summer night, with phone calls to make and records to comb, and the coroner's van departed as well.

INTERACTION: It's time for Noelle to do some research. In the comments, suggest topics for Noelle to dig up information about.

Agent Singh and Maria returned to a conference room on the third floor of the Saturn Technologies building and sat for a while, the silence broken only by the rustle of paper as Singh annotated documents neatly in red pen, and the faint bubbling of the coffeemaker on the counter next to the big table.

Maria knew what was going on. This silent treatment was meant to make her talk. But she'd already given as full an account of the evening as she could, even if the investigators didn't seem to believe it.

"Um," she said finally, "I really don't know how my gun got into Uncle Johann's office. I gave it to Felicity."

"Then what makes you think it was your gun?" replied Singh, still peering at her notes.

"It's not the kind of revolver you see every day. And there's a little damage on the butt where I dropped it."

"I can see why you'd think it was yours, then. Nonetheless, if you gave your gun to Felicity, it couldn't have been the gun at the scene."

"Well, the window was open," said Maria, grasping at straws. "Maybe someone used some kind of... slingshot to launch it up?"

"No." Agent Singh looked up wearily, as if to say, Surely you can do better than that. "I'm not saying it was impossible for your gun to have reached the scene. I'm saying the gun we found there could not be the gun you gave to Felicity."

Near the table sat a big, black box labeled with a cryptic series of numbers and letters. Agent Singh unlocked it, revealing an array of compartments, some climate-controlled, some sealed, and some ventilated. One slid out, and inside was a plastic bag containing a revolver. A chain of custody form, meant to ensure that the evidence wasn't tampered with. was attached to the sealed bag. It explicitly attested that after Maria found the gun, the only person who had handled it had been Singh herself, with gloved hands.

As soon as she had been notified of the shooting, she had insisted that nobody disturb the scene.

"This is the revolver you found. Note the chip." The butt was indeed damaged where Maria had expected it to be. "Now, your partner will be here in a moment, and I'll show you the problem with your slingshot theory."

Jeffrey, one of Singh's assistants, soon entered, with Felicity Crowe following behind. Felicity was the tallest person in the room by a few inches, and her posture was proud, even defiant, as she glowered down at Agent Singh. Singh, in turn, did not rise from her chair.

"So what the hell's going on? Are we being detained? Because if you're detaining us, we know our rights. You didn't say anything, did you, Maria?"

Maria's mouth dropped open for a moment. "Um," she replied.

"So you ran your mouth. Figures. But I'm not saying a damn thing till I've got a lawyer."

"Sure," said Agent Singh. "We'll see how that works out for you." She got up and poured a cup of coffee, which she offered Felicity.

"Oh, thanks," said Felicity, taking a sip. "Not bad."

"Are you protecting your partner? Do you think she could have done this?"

"What? No!" cried Felicity, shaking her head and waving her arms for emphasis and, in the process, splashing hot coffee on Maria's shoulder. Not noticing her partner's wince, she proceeded with a vigorous defense. "She wouldn't hurt anybody, much less shoot her uncle!"

"Mmm. I don't recall mentioning anybody being shot," replied Agent Singh. She reached over to the counter, grabbed a dishrag, and tossed it to Maria, who began dabbing up the spill in silence.

"Who do you think you are, freaking Columbo?" said Felicity, eyes widening incredulously. "I heard two gunshots from the other wing. Plus, I saw his body later. Geez."

"I see there's no fooling you," said Singh. "Is that a gun on your belt?"

"Maria's gun. She gave it to me. See... she didn't have a gun tonight."

Bewilderment flashed across Maria's face when she realized that Felicity's holster was indeed occupied. Singh simply pulled a fresh pair of gloves and a clean plastic bag from her box, then rose to her feet. "That makes it evidence. I'll need to take a look."

Grudgingly, Felicity turned over the revolver, and Agent Singh checked the cylinder. Fully loaded, and not recently fired. Strangely, its butt was chipped in exactly the same spot as the other revolver's. "Does this look familiar?" she asked Maria.

It did. "What's going on?" she whispered. "It looks exactly like mine."

"Doesn't this clear her?" asked Felicity. In response, Agent Singh walked back around the table and directed her attention to the identical revolver in the other bag. At that, Felicity could only shrug, left at a total loss.

"I swear I only owned one gun," said Maria, trying to keep a grip on the facts.

"You've told me as much," said Agent Singh. "A gift from your sister, right?"

"Yes," said Maria, then, anxious to avoid leading the investigation to a wrong conclusion, she added, "But she never said anything about buying two of them. I definitely never saw her with one."

Singh narrowed her eyes. It would have been easier, in some ways, if Maria had tried to pin the blame on her sister. Tragic and cowardly, perhaps, but her heart was hardened to human weakness. She didn't know what to make of this denial.

"My theory," she said, with deliberate slowness, "is this: these guns were purchased as a matched set."

"There's a way to check that, isn't there? Even if you don't take our word for it," said Maria, and then made a proposal.

INTERACTION: How could Agent Singh check this hypothesis without taking Noelle and Maria at their word?

Narration Unlocked by Librarysmiles:

Spoiler: Spoiler

"Noelle and I took photos of the serial numbers on most of the things we own," said Maria. "In case of theft, you know? There should be a photo of my gun's serial number of my phone, if you'll let me unlock it."

Agent Singh considered this. While there was no guarantee the photo Maria showed her would be accurate, it could do no harm to look. She pulled Maria's phone from the box, where it sat, confiscated, and let her unlock it. "Tracing purchase records can be a hassle," said Singh. "Your thoroughness is appreciated."

After a few moments of searching through her photo album, Maria found the photo. She'd taken it when disassembling the gun for cleaning, since the serial was concealed under the grip. "Here."

Taking the phone back, Agent Singh duly noted the serial number. Then, with gloved hands, a screwdriver, and the utmost care, she unscrewed the grip panels and gently levered them off the gun, moving them to separate plastic bags for fingerprinting.

The serial number on the frame underneath was the same as the one in Maria's photo.

While it seemed strange to Singh that a suspect would volunteer such incriminating evidence, she was not about to look a gift horse in the mouth. "It's a match."

"Then... what about the gun Felicity had?"

Singh repeated the disassembly process on the revolver Felicity was carrying. She read the serial number and copied it down, then stopped, and read it once more. This couldn't possibly be correct, could it?

Both guns were identical, all the way down to the serial number.