I'm sorry to throw up another 'maybe' but I just thought of something. Maybe you are thinking of the Harem conspiracy during the reign of Ramses III? It involves his wife Tiy, and her possible attempts to kill him (or was she framed?!) along with the rest of the Royal Harem:
In the Harem Conspiracy Papyrus, we learn of an assassination attempt upon the king in which Tiy was at least a part of the plot. Her name is provided in the text, but the other conspirators are called by names that indicate the great evil of their crime, such as Mesedsure, meaning "Re hates him". Tiy apparently wished for her son, called in this papyrus, Pentewere, to ascend to the throne of Egypt.
At some point during the latter part of Ramesses III's reign, there were economic problems that became most visible when the Deir el-Medina workmen failed to be paid, leading to a general strike, the first in recorded history, in the 29th year of the king's reign. Against this background was hatched a plot against the king's life.
This was no simple conspiracy, considering that at least 40 people were implicated and tried as a group. Amongst their numbers were harem officials many of whom were close to the king. Not only had they intended to kill the king, but also to incite a revolt outside of the palace in order to facilitate their coup.
The plot was seemingly hatched in Piramesses where one of the conspirators had a house. The plan called for the murder of the king during the annual Opet Festival at Thebes. Preparations for this included magical spells and wax figurines which were smuggled into the harem.
This conspiracy is thought to have failed, and the guilty were charged and brought before a court consisting of a panel of fourteen officials including seven royal butlers (a respectably high office), two treasury overseers, two army standard bearers, two scribes and a herald. Ramesses III himself most likely commissioned the prosecution, but according to the language of the papyrus, probably died during the trial, though not necessarily from the effects of the plot. Curiously, this court was given authority to deliver and carry out whatever penalty they deemed fair, including the death penalty, which normally only the king could inflict. It should be noted, however, that scholars are in disagreement over the events of this conspiracy. Some maintain that Ramesses III was in fact killed by the conspirators, and that his son, Ramesses IV, set up the tribunal, but others maintain that the mummy of the king shows no acts of violence.
All of those involved in the plot were apparently condemned to death, as was certainly the fate of Queen Tiy herself. Though the record of the actual trial is lost, there were apparently three different prosecutions. The first consisted of twenty eight people, who included the major ringleaders, who were found guilty and (almost certainly) put to death. In the next prosecution six people were condemned and forced to commit suicide within the court itself. In the final trial, four additional individuals, including the son of Queen Tiy, were likewise condemned to suicide, though they were presumably allowed to carry out the act in their prison.
Interestingly, there was also a fourth trial, but this one did not involve the actual conspirators, but instead three of the judges and two officers. It would seem that the curious affair resulted from accusations that, after their appointment to the conspiracy commission, they knowingly entertained several of the women involved in the plot, as well as consorted with a general referred to as Peyes. Though one of the judges was found innocent, the remainder of the group was condemned to have their ears and noses amputated. One of the judges called Pebes committed suicide before the sentence could be carried out.
Whether this is relevant I do not know, but I saw simmilarituies in my mind between the two and copied this article out for you. Essentially, Ramses III was killed, and Tiy, one of the king's most trusted wives was killed. This happened supposedly after his death, so it fits in with what you said. However, Tiy was significantly younger than Ramesses III, who was very old and presumably quite ugly by this stage in his life. Ramesses III is buried in KV11 in the valley of the kings, and it is unlikely that a potential assasin would have been allowed anywhere near the body, let alone to keep it!
I did start typing one out for you, but I hit the back key by mistake and I lost it all! Grr!