I forgot - Gallius denies ordering the rest of the turb to go anywhere, especially as that would involve sending his two sodales at Tribunal's shield grogs off. He knows nothing of any noble he claims. Cedric insists they left, having told him to stay at Tribunal, and departed soon after the session began, to meet the knight of the lion at the sign of the Cross Keys, some twenty miles off - presumably an inn. They are expected back tomorrow.
cj x
I would ask the Praeco if he would humour a request and either cast himself, or allow someone to cast in his stead, the Inexorable Search (InCo20, from the corebook, locates a person given an arcane connection to that person) using the letter addressed to him as the arcane connection to the target.
If the writer is the dead maga, all is well, and this does not count as scrying. If the writer is some other magus, he is certainly attempting to violate the Code (among other things, because such a letter may endanger Gaius), and thus his protection from scrying under the Code is forfeit.
I guess the first question that probably anyone would ask Cedric under Frosty Breath of the Spoken Lie -- particularly considering that his version of how he killed the maga appears to differ from what the Corpus spells suggest -- would a be a detailed description of what transpired, from when he saw the maga emerge from the Tribunal chambers to when she died, basically confirming that, in order:
If this is all confirmed by the grog and by the spell, there has obviously been magical tampering with the grog's memories or perceptions.
I would suggest an examination by physician and InCo of the corpse to check for incurable fatal conditions - cancers, well hidden decrepitude etc.
I would also check out the apprentice. Happily she is not yet a maga and her hermetic owner is dead - question her under frosty breath about events at this tribunal starting with "Are you really Rhiannon?" and going on about what she knows about Rhiannon's plans and actions over the past few days if the answer is no. Also "are you responsible for Rhiannon's death?"
I suspect either a spiteful last act by someone who knew she was dying or some sort of body swap shenanigans (hinted at by the lack of a shade) and Alyssa as heir is the most likely candidate to have been pithed and taken over. She is also a suspect in her own right although it's hard to see how an apprentice could have set this up.
Seconded. At this time the apprentice is the most likely suspect, or at least her body, probably with Rhiannon's spirit. I would have her investigated as well. Since Rhiannon's Parma was blown down, the apprentice should be without the benefit of one. She has not been officially Gauntleted, so she should not know that secret. If she is protected by Parma, then this increase suspicion that this is in fact Rhiannon. If she is not, and is proven not to be Rhiannon, then questionning her may yield additional information. As mentioned, she has no protection under the code. Her mistress is supposedly dead. She is not a maga sworn to the Code.
I would ask her both general questions and some very specific one about the situation, being careful with wording. "Do you know anything of the murder of what appears to be Rhiannon?" "Are you Rhiannon spirit in Alyssa's body?" "Do you know the whereabouts of Rhiannon?" "Did you conspire to make it look like Gallius murdered Rhiannon?" "Was Rhombia complicit in such conspiration?"
Note that an arcane connection should be obtained from "Alyssa" before any spell is cast upon her, in the case she is actually Rhiannon.
I'm not sure Inexorable Search would work in this case, but a variant will suffice. As it's a ritual I'll just assume there was one on a Casting Tablet in the covenant. Anyone care to design the spell?
OK, Rhiannon (or her corpse) wrote the letter.
cj x
The corpse seems to be elderly and of the right age for Rhiannon. No fatal afflictions can be detected.
The apprentice appears terrified, and argues that if she is interrogated she will inadvertently reveal secrets of RHinannon (no longer relevant) but also other maga who belong to Rhiannon's esoteric mystery cult, and as such she refuses to participate. She denies being Rhiannon with a sharp outcry of "Rhiannon is dead, Fool!" and states that Rhiannon came to Tribunal in fear of her life from that fiend Gallius, "who has long persecuted her for no reason!"
Rhiannon refuses absolutely to hand over an Arcane Connection, or participate further in the investigation. She turns to walk out of the Tribunal.
So, Day 1 is up. I could explain what is going on, but better let you people decide; but who should be tried, on what charges? And then we should vote really on outcomes. 
If you wish to investigate further and time permits I shall answer tomorrow, but I'm going to put up Day 2's case in a little while. Hope you have enjoyed The Case of the Murderous Grog? Hopefully it can be adapted for use as a mini scenario or Story Seed in some folk's games.
Also If like to ask David Chart if magi are legally accountable for their shield grogs actions?
cj x
is that an admission of her true identity then? Or a claim of being Rhiannon at least? If not, we weren't asking we were ordering the piece of unclaimed hermetic property to submit to our investigation. Does she resist? She doesn't need both feet to answer questions.
I have enjoyed it thanks!
If spells are used to try and stop her, yep she has Parma Magica! Illegal in an apprentice...
Case 2 now up
https://forum.atlas-games.com/t/case-2-the-case-of-the-unfortunate-apprentices/7374/1
Hmm... should this be called "the case of the murdering apprentice"?
As has been pointed out, since Alyssa is not a magus, nor is the servant of a magus, InMe spells should be used to pry out whatever she remembers of the scene in which her mater was killed. This would not violate the proscriptions against scrying, since the only parties present at the time appear to have been Rhiannon (now dead), a grog, and Alyssa herself -- so no risks to Rhiannon's fellow mystae.
I love this all!
Furthermore, if she does not submit to rigorous interrogation and still deny being Rhiannon, as an apprentice she can be destroyed on the spot for illegally knowing Parma Magica. It would not be depriving a magus of his magical property, since she claims that Rhiannon is dead. If she admits (or is found through investigative spells) to be Rhiannon, then she has attempted to deprive Gallius of his magic by submitting him to an uncalled for Wizard's March. If she cooperate, she may avoid being Marched herself.
Rhombia may also being investigated for complicity to deprive a magus of his magical power. She was very quick in calling for Gallius to be Marched, suspisciously so. If she is found guilty, a relatively severe penalty, such as the loss of an apprentice, familiar or talisman, may be called for. I would advise her to cooperate fully and submit to InMe verification of her innocence.
Such attempted entrapment of a member of the Order, by trying to manipulate Tribunal, is contemptible and calls for severe punishment.
Great case! 
First off. Kudos on this excellent idea and a very interesting read. Really enjoying it.
Secondly, about the case.
Seize the apprentice. Explain to her the options.
Claim identity as a known magus of the order (including the slain magus) and suffer the wrath of the tribunal for trying to mislead them.
Claim identity as the apprentice of the murdered Magi and have the true details ripped from her head by magic until everything is learnt, then be destroyed (unless some REALLY good extenuating circumstances are revealed) for knowing the Parma while not being a magus.
claim identity as some other being and suffer the wrath of the tribunal for trying to mislead them.
Either way the apprentice is clearly in a whole world of hurt. She is currently under sentence of death for knowing Parma without being a magus and will need to be as open as possible if she wants any chance of surviving the tribunal.
I second the other's suggestions - seize Alyssa! One way or another, she's going down.
I would note that her Parma might be due to some other magus' skill, so that I would not consider it clear evidence that she has the skill and is to be destroyed (if she is still Alyssa). However, in that case she still needs to be stopped and investigated magically, and her Magic Resistance would, I am sure, not be able to stop the resident Hoplites from gleefully discharging this duty for the gathered tribunal.
Yairus of Criamon
Hearing that Rhiannon was part of a mystery cult and a powerful Mentem maga adds credibility to Noliar's idea that Alyssa could really be Rhiannon, in mind if not in body.
If so, the crime is entirely different - there is no murder, but only an attack aimed at Gallius and an attempt to mislead the Tribunal.
Does anyone want to claim a slightly battered, orphaned apprentice ? I know a Tytalus magus or two who wouldn't mind shaping her into a proper maga...
Case 3 The Case of the Diabolical Pride - up now, a little early. https://forum.atlas-games.com/t/case-3-the-case-of-the-diabolical-pride/7377/1
Case 4: The Case of the Reluctant Redcaps -- now up here - https://forum.atlas-games.com/t/case-4-the-case-of-the-reluctant-redcaps/7381/1
OK, for those of you who followed this one (Case 1) from the beginning, let's hear your theories...
Just give your reconstruction of events. I'm curious as to who comes closest now! 
cj x
A few spells cast on the apprentice should show the truth of the story since she is present during the whole scene in any case.
Nice story in any case. More of a murder mystery than a law tribunal case, but really cool.