A young influencer was fatally shot by a motorcyclist as he was streaming video to his followers in a city at the center of Mexico’s cartel wars on Tuesday night.

The influencer, César Gastélum, whose comedy videos had gained him more than half a million followers on TikTok, was dressed as a fast-food worker as he and two friends completed a social media challenge outside a KFC restaurant in the city of Culiacán, in the Mexican state of Sinaloa.

Mr. Gastélum, who local news outlets have said was 24, died at the scene.

Experts say that Mexican cartels are increasingly targeting influencers, who can be caught up in violence after they post content that praises or refers to one group, sparking the anger of another.

In Culiacán, where Mr. Gastélum was shot, a plane dropped fliers last year that named two dozen people, including influencers, as being loyal to one cartel faction, Los Chapitos. (Mr. Gastélum’s name was not on the list.)

“They become targets,” said Víctor Sánchez Valdés, a security expert and researcher at the Autonomous University of Coahuila in Mexico. “It’s a national phenomenon, but it’s been accelerating because of recent changes within cartels.”

In May 2025, a 23-year-old Mexican beauty influencer was fatally shot during a livestream at her salon in the state of Jalisco.

The Mexican authorities said the attack on Mr. Gastélum could have been related to some of his posts on social media, which they said had alluded to “a faction of a criminal group,” though they did not say which one.

Mr. Gastélum was approached by a two men in helmets on a motorcycle around 8 p.m. on Tuesday. In the video, which was streaming on the Kick platform and has since been taken down, Mr. Gastélum could be heard saying, “Those guys scare me,” after the motorcycle first appeared near the group, according to news outlets.

The motorcycle then circled back and one of the men could be seen drawing a handgun and firing directly at Mr. Gastélum’s head.

Rival factions of the Sinaloa cartel have been fighting for dominance since 2024, when one of the cartel’s founders and its longest-serving leader, Ismael Zambada García, known as El Mayo, was arrested in the United States.

Mr. Zambada García arrived in the United States in July 2024, after one of his partners, Joaquín Guzmán López — a son of Joaquín Guzmán Loera, known as El Chapo — lured him onto a plane under false pretenses before flying him to an airport outside El Paso, Texas.

After his arrest, Mr. Zambada García’s followers, Los Mayos, went to battle against Los Chapitos, the faction loyal to the sons of El Chapo, who was arrested a decade ago and is serving a life sentence in the United States.

Both factions have military-grade weaponry, armored vehicles and drones, and have fueled intense violence across Sinaloa state and in the cities of Culiacán and Mazatlán.

President Claudia Sheinbaum of Mexico addressed Mr. Gastélum’s killing on Wednesday in her morning news conference, confirming that the case had been discussed in a security cabinet meeting and pledging to find those responsible.

“The perpetrators, and the mastermind, must be detained, and the reason for this tragic homicide must be uncovered,” she said.

Residents of Culiacán, Sinaloa’s capital, have been living in a state of near-lockdown as the Chapitos and the Mayos have battled, setting up roadblocks and exchanging gunfire in broad daylight.

Because of this, classes are often suspended and businesses operate on reduced hours. The number of homicides has ballooned — to 1,086 in 2025 from 623 in 2024, according to official government figures, making Culiacán the most violent city in Mexico last year.

Outside Sinaloa, cartel violence has also roiled the world of Mexican influencers and content creators.

The authorities say that the on-camera killing of the Mexican beauty influencer, Valeria Márquez, last May in Jalisco was related to cartel violence.

Last month, Mexican special forces carried out an operation to arrest a leader of a criminal cell of the powerful Jalisco New Generation Cartel, known as “Los Rs,” who has been accused of playing a role in Ms. Márquez’s killing.

Omar García Harfuch, Mexico’s security secretary, said the cell leader, Ramón Ángel Álvarez Ayala, known as “El R-1,” was the father of a man who had been in a romantic relationship with Ms. Márquez and who had threatened her life.

“Everything indicates, and this will be proven, that the son asked his father, El R-1, to carry out the femicide,” Mr. García Harfuch said. Mr. Álvarez’s son, Francisco Álvarez Solorio, has not been detained.

Officials have also accused Mr. Álvarez of planning and financing the 2025 assassination of a mayor, Carlos Manzo, who vowed to target cartels in the state of Michoacán.