An unnamed witness has said "Rust" film armorer Hannah Gutierrez Reed "transferred a small bag of cocaine" after returning from a police interview on the day of the "Rust" fatal shooting, according to a motion filed by prosecutors Thursday.

The new filing comes after prosecutors last week charged Gutierrez Reed with tampering with evidence in relation to the shooting death of the movie's cinematographer Halyna Hutchins, according to an amended complaint filed last week. The charge is in addition to two counts of involuntary manslaughter filed against Gutierrez Reed earlier this year.

"The prosecution team has been in contact with a witness (hereinafter referred to as SI) who will testify that the defendant transferred a small bag of cocaine to SI on the evening of October 21, 2021, after the defendant returned from her interview at the police station on the day of the fatal shooting," a state's opposed motion to protect the identity of witness read.

"The circumstances of the transfer of evidence strongly support the charge that the defendant transferred the cocaine to avoid prosecution and prevent law enforcement from obtaining highly inculpatory evidence directly related to the defendant's handling of the firearm and the circumstances of the fatal shooting of Halyna Hutchins," the document added.

In the motion, the state is asking to protect the identity of the witness and other potential witnesses "from economic reprisal from the film industry and intimidations, annoyance, and embarrassment from the media for as long as possible."

"Without some protection from the court, witnesses will be extremely reluctant to come forward and provide the truthful information that is necessary for the special prosecutor to obtain justice for the victim in this case," the document read.

Gutierrez Reed's attorney called the new charges "character assassination."

"A secret witness who suddenly appears 20 months later? Where's the actual evidence of anything?" Gutierrez Reed's attorney Jason Bowles told CNN. "This is more of the same underhanded, secret, reprehensible tactics from the state."

CNN previously reported Gutierrez Reed transferred narcotics to another person "with the intent to prevent the apprehension, prosecution or conviction of herself," an amended complaint said.

Gutierrez Reed was likely hungover when she loaded a prop gun used by actor Alec Baldwin that fired a live round of ammunition during a rehearsal, prosecutors alleged in a prior court filing.

Last week her counsel responded to the new charge by saying, "It is shocking that after 20 months of investigation, the special prosecutor now throws in a completely new charge against Ms. Gutierrez Reed, with no prior notice or any witness statements, lab reports, or evidence to support it."