She said transgender women of color exist at the “intersection of multiple forms of violence which are also about race, misogyny, poverty and a system that reinforces the fallacy that we shouldn’t exist and don’t exist.”

A suspect was arrested and charged with Ms. Clarke’s killing after the police found DNA evidence and a condom that contained fluid in her car. There have been no arrests in Ms. Capri’s death, according to ABC 15 in Phoenix, but her family is seeking a hate crime investigation. And authorities say there is no update in Kenton Haggard’s case.

Mr. Hayashi said that transgender people faced a system of discrimination — which includes lack of access to health care, education, housing and job resources — that can result in people who put themselves in “really vulnerable positions as far as the violence that we’re seeing.”

The organization receives about 2,500 calls a year from transgender people and their families seeking assistance, Mr. Hayashi said. The demand often outweighs the resources.

Mr. Jenson, of the Kansas City Anti-Violence Project, said that lengthy police investigations, sometimes carried out in a way that activists feel lack dignity and thoroughness, had sometimes led to tension between officers and the communities they serve.

“We get told by agencies that we’re hindering the process or hurting our communities because they don’t understand hate crimes or how it could work,” Mr. Jenson said. “It’s not a community’s job to have to educate themselves on such a nuanced system and hate crime laws that do not actually work.”

Tension has also occurred over how the gender of a person who either publicly or privately identifies as transgender is reflected in a police report: In Tampa, Kansas City and Fresno, the police referred to Ms. Clarke, Ms. Dominguez and Kenton Haggard by their legal — male — names, which offends activists. And questions have been raised, particularly in the case of Kenton Haggard, over whether the victim publicly identified as transgender at all, though activists include the killing in the summer’s count of fatalities.