For the third time in less than a year, the Dallas police said Monday that they were investigating the killing of a transgender woman, raising the specter of a spree of violence targeting one of the most marginalized communities in the city.

Image Chynal Lindsey, whose body was pulled out of White Rock Lake on Saturday, bore signs of “obvious homicidal violence,” the police said. Credit... Dallas Police Department

The police said the woman, Chynal Lindsey, 26, was pulled out of White Rock Lake on Saturday afternoon. Her killing was the second in two weeks of a black transgender woman in Dallas, and she was the fifth transgender woman in three years to be violently attacked or found dead in the city.

At a news conference on Monday, Chief U. Reneé Hall of the Dallas Police Department said Ms. Lindsey’s body bore signs of “obvious homicidal violence.” When asked if there could be a serial killer hunting transgender women in the city, Chief Hall urged people to remain calm.