(CNN) The body of a transgender woman was found in Dallas over the weekend, in what police say is the second slaying of a transgender woman in the city this year.
Chynal Lindsey's body was found in a lake on June 1, Dallas Police Chief U. Reneé Hall said Monday.
Hall said Dallas police have requested the FBI's help in solving Lindsey's case and the killing of Muhlaysia Booker, another transgender woman who was found shot to death in South Dallas on May 18.
Their deaths bring the total number of open, unsolved homicide cases involving transgender victims to four, Dallas police Maj. Vincent Weddington said Monday.
In addition to Lindsey and Booker, the number of open cases includes homicides from 2018 and 2015, Weddington said. All of the victims are African American women, he said.
It is not clear if the killings are related, Hall said. But she urged the public to come forward with information.
"We are concerned," Hall said. "We are actively and aggressively investigating this case."
Booker's death just five weeks after she was assaulted by a mob drew attention to the pattern of violence against transgender women of color. It also renewed police's interest in the other cases involving transgender people in Dallas.
In the wake of Booker's death, activists and civil rights groups said that the number of homicides of transgender people could be higher than reported by police because, for a variety of reasons, victims are identified as the wrong gender, or their deaths are often not reported or not investigated as homicides.
Advocates also cautioned against viewing the pattern of violence as unique to Dallas.
In a press conference last week, Weddington said the department is investigating possible links between Booker's slaying and other acts of violence involving transgender women, including the stabbing of another transgender woman in April.
Hall said the FBI will help determine if the killings constitute hate crimes. Although it's unclear if hate crime charges are possible under Texas law, which does not include protections for transgender individuals, federal prosecutors could consider charges.
PHOTOS: Remembering Muhlaysia Booker
Community leaders and elected officials joined Booker's family and friends in celebrating her life at a funeral last week.
Faith leaders urged the wider Dallas community to stand in solidarity with Booker. Elected officials condemned the violence that befell her. But activists and those closest to Booker said they wanted to see actions behind those words.
One of Booker's friends -- another black transgender woman -- was present for Monday's press conference.
Jazmine Bandz asked the chief what the department is doing to "stop the violence against people like me" and make transgender people of color feel safe.
"That's our goal, to provide safety for each and every member of the community," Hall said. "We're working together to make sure that you can feel safe in the community."