[4] use electronic pings to look for any nearby governance implants in a dead body
[3] retrieve and then wipe all data from items/implants
You sort through the box, activating the personal area network on the decoys, transferring all the data, wiping it, then placing them in standby mode. A preliminary reconstruction, mostly from the accelerometer data, reveals a struggle, Ryouko's personal area network going offline, some sort of gentle low-gravity fall (the labyrinth collapsing?) then her body being found in the evening and transported somewhere via motor vehicle, presumably here. Then the decoys were removed Tuesday, mostly left inert, then further handled Wednesday evening and this morning.
The problem is, they're meant to be part of Ryouko's personal-area network, and they're specialized devices. The audio processing in particular is finely tuned for combat, helping to answer questions of here is an incoming shell, try to deflect it instead of niceties like people talking about things, and even that relies in part on Ryouko's own magically enhanced hearing (and even tries to take advantage of her enhanced reflexes).
If Ryouko's body is still around here, the implants will be on standby now, conserving power until they can detect a governance locator signal. You don't have the credentials for a general purpose signal, but you can manage one for Ryouko's implants specifically, if they're anywhere around here…
But there's no reply. Either there isn't a body anymore, or it just isn't here.
Where would it be? A secret lab of some sort? That's probably too paranoid, they wouldn't notice anything too strange unless they did a really involved autopsy, which they probably wouldn't. Not on short notice, not the regular police, right?
… Regardless.
[7] Disavow ownership of items
-[6] admit that they're sort of Ryouko's style
You place the decoys in a standby mode — they're still glowing, but will turn themselves off after a little while. You spend a few moments sifting through the contents of the box for show, while making a few Internet queries to calibrate contemporary clothing standards in case they come up.
"Well," you say, unfolding the dress, "It's kinda cute, I guess. I'm pretty sure it isn't something I've ever worn, if that's what you're asking. I'd have questions if it was. Not sure if any of it is my size, either."
"And how about either of your sisters?" asks the detective.
"I guess if it were one of them, it'd probably be Ryouko?" you offer. "But again, I'd have serious questions about how it got here. Unless you know something about stalkers which we don't?"
"Nothing like that, no," says the detective.
They send you into another room to wait by yourself, "just for a few minutes" (presumably so that you don't get to share information), and bring in Hitomi, who mostly answers questions about her day at school, but the questioning appears to be a bit of a formality while the men behind the two-way mirror discuss whether she's the person they're looking for.
"That's got to be her, chief," says unidentified voice #2. "I'm telling you. She just got up and left."
"Uh-huh," says unidentified voice #1 from before, presumably the chief, who seems distinctly unimpressed.
The other detective, Mr. Mitsuhiro's partner, urges restraint.
Mr. Mitsuhiro finishes his questions, leaving the box to the side.
"Would you wait here a moment?" he asks Hitomi.
He then steps outside, to retrieve you from where you are waiting, returning you to Papa, and then escorts Ryouko into the room with Hitomi. Instead of questioning either of them, however, he proceeds back outside and around to another door — the observation room, where observation appears to have given way to a personnel dispute.
"I thought I heard you say it's definitely her," says the chief. "Now it's definitely the other one?"
"Aw, come on, man!" says the underling. "Like you can tell them apart either."
"Whoa," says Mitsuhiro, walking in on the scene. "That does seem pretty unfair, Chief."
"I need you to shut it, Mitsuhiro," says the chief. "This is between me and Shiina. I'll talk with you later, k?"
"… Chief?" he asks.
"If this were the first time or something, it'd be another matter," continues the chief, "but it's a god damned pattern with you, Shiina, and no, I am not accepting reanimation, or anything supernatural, as an excuse…"
About this moment you get a call over the Governance mesh. It's Sayaka; she's downtown near the hospital.
"Hey, Sayaka," you begin, "what's hap—"
"Clarisse okay quick listen I'm down at the hospital," she interrupts, "and there's this … glowing … black … thing, in the wall here, and I'm pretty sure it's magic. That's a grief seed, right? And there's a witch somewhere nearby?"
She sends a picture of a grief seed, embedded in the wall outside the hospital by some parked bicycles. It's glowing ominously.
Oh, goddess, you think to yourself. Why does this have to happen now, of all times?
Because Kyuubey waited until he knew you were busiest, suggests a paranoid part of your thinking.
"… yes!" you affirm to Sayaka hurriedly. "Grief seed. Get away from there, quickly! You could be in danger."
"But what about the people here?" insists Sayaka. "They could be in danger too…"
That's right, her boyfriend's at the hospital…
You do a quick check of Nanami's location; she is not super close.
> help Sayaka?
[] Insist to Sayaka run away, Nanami's on it
[] Tell Sayaka to wait there for Nanami
[] Attempt to reach Homura on her cell phone
[] Have Ryouko teleport away in the mild distraction, fight the witch
-[] do a flashy transformation sequence first
-[] … remove the box while she's at it.
[] Have Ryouko ask to use the ladies' room, then teleport over to help
[] Visit the ladies room yourself and get Ryouko to teleport you over to:
-[] relay Nanami to Sayaka's location
-[] physically extract Sayaka
(Either of these relays would be an experimental channeling of Ryouko's magic.)