BALTIMORE (WJZ) — On the two-year anniversary of her disappearance, a bombshell is dropped in the murder of Phylicia Barnes, the 16-year-old later found floating in the Susquehanna River.

Prosecutors said they have a video showing her engaging in sexual acts with her accused killer.

Meghan McCorkell has details on the court papers.

The existence of the sexually explicit tape was made public Friday in court documents. It’s something the defense is calling a game changer. They said it shows the teen “intoxicated and engaging in sexual relations” with her accused killer, 28-year-old Michael Johnson, his younger brother and her half sister, Deena.

Johnson is accused of asphyxiating Barnes in December 2010, putting her body in a 35-gallon plastic tub and dumping her in the Susquehanna River.

According to court documents, the 16-minute, 31-second explicit video was recorded and stored on the cell phone of Deena Barnes.

She spoke with WJZ after her sister went missing.

“Of course it’s been hard, especially with us not knowing, you know, where she is or any changes,” Deena said in February 2011.

Word of the sex tape was made public when prosecutors filed a motion to close the courtroom while the video is played during trial.

Johnson’s attorney, Russell Neverdon, has seen the tape.

“We were really caught off guard by this, and it does change strategy somewhat,” said Neverdon.

He believes it strengthens the defense’s case since prosecutors claimed Barnes told her sister she didn’t like the way Johnson looked at her and he made her feel uncomfortable.

“They referenced that Phylicia reportedly was very uncomfortable and felt shaken based on sexually inappropriate actions that Michael supposedly made to her. Unfortunately, this tape shows a completely different light,” said Neverdon.

Neverdon says he didn’t plan to use the tape, out of sensitivity for the Barnes family.

But it appears prosecutors have decided to use it. They’ve also filed a motion to seal the tape at the conclusion of the trial, calling it child pornography.

The murder trial is set to begin Jan. 22.