Federal prosecutors say Matthew Perry's assistant, Kenneth Iwamasa, did more than manage the actor’s household after Perry died. In a new court filing obtained by TMZ, they allege the former live-in aide tried to erase evidence tied to the ketamine conspiracy at the center of the case.

What prosecutors say happened after Perry’s death

According to the filing, prosecutors claim Iwamasa moved quickly into damage control after the “Friends” star died. The alleged cleanup was not limited to tidying a scene, which is rarely the part investigators find most interesting.

Federal prosecutors say Iwamasa directed another person to dispose of items connected to ketamine use, including vials and syringes. That person is identified in the filing as “B.M.”

They also allege Iwamasa ordered the shredding of two documents:

  • A ketamine prescription document
  • A handwritten note identifying Dr. Salvador Plasencia as a ketamine source

Prosecutors say those steps were meant to hide where the ketamine came from and how it was handled after Perry’s death.

Investigators allege he lied about injections and bottles

Prosecutors also accuse Iwamasa of repeatedly misleading investigators.

They say he first hid the fact that he had injected Perry with multiple ketamine shots on the day the actor died. Later, according to the filing, he claimed Perry had hidden ketamine bottles himself.

The filing says that version was not true.

The alleged statements matter because Iwamasa has argued he was acting as an assistant following Perry’s instructions. Prosecutors are now pushing back on that framing, saying his conduct went beyond carrying out tasks for an employer.

The phone call prosecutors are pointing to

The filing also cites an alleged phone call between Iwamasa and middleman Erik Fleming.

Prosecutors say Iwamasa later admitted during that call that he had “cleaned up the scene,” disposed of bottles and syringes, “deleted everything,” and changed passwords on Perry’s devices.

Prosecutors say that matters because it goes directly to intent. Put plainly, prosecutors are arguing this was not a confused assistant responding to a crisis, but someone taking steps to destroy or hide evidence after a fatal drug-related event.

Why the trust issue is central to the case

Federal prosecutors say Iwamasa abused the trust placed in him by Perry and by Perry’s family. The filing says the family believed he was supposed to help protect Perry while the actor was dealing with addiction struggles.

That argument appears aimed at sentencing. Prosecutors are not just describing the alleged cleanup; they are framing Iwamasa’s role as one that involved responsibility, access, and a duty of care he violated, in their view.

Iwamasa pleaded guilty in 2024 to one count of conspiracy to distribute ketamine resulting in death as part of a plea deal with federal prosecutors.

Prosecutors are seeking 41 months in prison. Iwamasa is scheduled to be sentenced on Wednesday.