The cellphone recording of the single gunshot that killed 15-year-old Warren Grant echoed throughout the courtroom Wednesday as dozens of Grant’s friends and family relived the moment he was fatally shot in a dispute over a girl in a Joppatowne High School bathroom in September.

Jaylen Prince, 16, of Edgewood, is charged as an adult with first-degree murder, first- and second-degree assault and the use of a firearm in the commission of a felony for Grant’s death.

Prince attended Joppatowne High School on the fourth day of the school year, prosecutors said. On his first day, the teen wore a backpack, which is prohibited, according to school officials.

Leading up to the shooting, Magness Douala, 18, Prince’s friend who worked at Walmart with him, said the two were roaming the school together.

Douala said they ran into Grant’s girlfriend outside of the cafeteria and Prince flirted with her. Douala testified he told Grant and later advised Prince not to flirt with Grant’s girlfriend anymore.

The advice, Douala said, agitated Prince.

Douala and Prince stopped by a bathroom before fourth period.

Douala testified that Grant was one of several students in the bathroom.

A verbal altercation ensued between Grant and Prince, which witnesses say was initiated by Prince. Student Julian Mueller was inside the bathroom and testified that Grant told him to “record” what was going on.

In Mueller’s video, Grant and Prince are seen arguing and moving toward the bathroom entrance where Prince was allegedly blocking the door — and preventing Grant from leaving.

At the moment Grant tried to leave, Prince had his backpack off and open, Mueller and Douala testified. Inside the backpack was a 9mm, privately built Polymer80 handgun that prosecutors referred to as a “ghost gun.” The gun was never recovered after the shooting.

The video shows a physical altercation between Grant and what appeared to be Prince. A gun can then be heard cocking, as Prince says, “I will kill you in here,” and the gun is fired.

An audible gasp could be heard in the courtroom gallery as Grant’s body falls backward and students in the bathroom video scramble.

The single shot sent panic throughout the school with health and physical education teacher Nathan Brungot, just across the hall, testifying that he quickly locked his door, shuffled his students into a corner and called police.

Mueller said he dropped his phone and ran to Grant’s aid.  The students can be seen on school surveillance footage carrying Grant’s body from the bathroom and toward “the center of the school” where Mueller said there was a library.

“We took him there because we knew that’s where the teachers were,” Mueller testified. “We wanted to get him help.”

Mueller said he held Grant’s head as other students applied pressure to the gunshot wound and tended to him on the floor. Grant was later transported the hospital where he died.

Throughout the testimony, Grant’s friends and family sobbed, patting their eyes and comforting each other. Grant’s mother often held her face in her hands with a distraught look on her face before leaving moments before her son’s death was shown to the court.

Harford County State’s Attorney Alison Healey said Wednesday that the medical examiner, a Joppatowne High School student and Harford County Sheriff’s Office personnel are expected to testify Thursday.

Have a news tip? Contact Matt Hubbard at mhubbard@baltsun.com, 443-651-0101 or @mthubb on X.