After a model and his friend were charged with the murder of Harry Uzoka, also a model, earlier this week, commenters on the internet speculated that the motive was professional rivalry.

But on Thursday, at the defendants’ first hearing in the central criminal court of England and Wales, the prosecutor said that Mr. Uzoka’s death was the result of a conflict over a woman, according to Lorelei Marfil, a Women’s Wear Daily editor who observed the proceedings from a public gallery.

Mr. Uzoka, who has appeared in campaigns for G-Star Raw, Everlane and Levi’s, and was represented by Premier Model Management, was found injured from a stabbing last Thursday afternoon near his home in West London and was pronounced dead shortly after, BBC News reported. George Koh, one of the defendants, has worked with Paul Smith and Hero Magazine and was represented by IMG Models until March 2017.

Ms. Marfil’s account includes the prosecutor saying that Mr. Uzoka and Mr. Koh had planned the fight over direct messages on Instagram, and that Mr. Uzoka and a friend were armed with metal pipes, while Mr. Koh and the second defendant, Jonathan Okigbo, arrived carrying knives. A third person, yet to be named, brought a machete-like knife.

The prosecutor added that Mr. Uzoka was chased by the attackers and stabbed three times in the heart, and that Mr. Koh turned himself in to the police on Monday, saying that he acted in self-defense.

Tributes and condolences for Mr. Uzoka’s family and friends poured out on social media, including from Michaela Coel, the creator, writer and star of the British television show “Chewing Gum”; and Jacob Banks, a musician.

Leomie Anderson, Mr. Uzoka’s ex-girlfriend and a fellow model, posted photos of herself and Mr. Uzoka on her Instagram page and wrote, “you’ve been all over the world and been an inspiration to so many. You are proof that you can change your entire life and become a role model, no matter the circumstances. So much I want to say, so much I feel and don’t feel right now but just know you are loved, you are love and light and I just can’t believe this.”