D.C. police are investigating four recent attacks — including a homicide — involving gay or transgender victims, although authorities have not classified any as hate crimes.

Two incidents stemmed from disputes, and two were attempted robberies, according to police. Advocates for the gay and transgender communities, including the co-chairperson of Gays and Lesbians Opposing Violence, say two of the cases show elements of hate crimes.

The unusual number of incidents has put the gay and transgender communities on edge, even prompting leaders to schedule a meeting late Friday at the DC Center on U Street NW. Earline Budd, founder of a group called Transgender Health Empowerment and the meeting’s organizer, said the attacks must be addressed regardless of motive in order to keep a vulnerable population safe.

“It’s about folks being on alert,” Budd said.

The attacks came amid a historic week for gay rights, in which the U.S. Supreme Court struck down a key part of the federal Defense of Marriage Act and, in a decision not to hear a California case, paved the way for that state to resume recognizing gay marriage. There is no indication, however, that any of the recent violence in the District is related to the rulings.

Although police have not deemed any of the incidents hate crimes, officials confirmed that the department’s Gay and Lesbian Liaison Unit is involved in two of the investigations.

The first in the series of attacks occurred early June 21, when patrol officers responded to a stabbing in Southeast Washington. Police said a transgender woman told officers that she and an acquaintance had argued over $40 for sex.

According to Budd, however, the victim said she met the man to get a cigarette. She said a friend of the man spotted the two together and made an offensive comment about his being with a transgender woman. Budd said the victim thinks the man stabbed her to impress his friend.

Police said the victim, who has been released from the hospital, was stabbed 11 times, suffering a collapsed right lung and severed tendon in her left hand. Police have charged Michael McBride, 23, of Southeast with assault with intent to kill.

About 8:15 p.m. Saturday, a 35-year-old woman was shot and killed in the 1300 block of Stevens Road SE, police said. Budd said the victim was a lesbian well known in the gay community. She did not know the circumstances of her death, but police said the motive appeared to be attempted armed robbery.

“This has not been classified as a hate crime,” said Officer Araz Alali, a D.C. police spokesman. Relatives of the victim could not be reached.

Next, police responded Sunday to Manny & Olga’s pizzeria at 14th and U streets NW, where a man dressed as a woman reported being attacked after performing at a drag show at the nearby Black Cat club. The victim told the Washington Blade that he identifies as a gay man.

A bystander shot video and appears to have encouraged the fight that left the victim bleeding from the head.

The video, posted on the Internet, documents an argument between a woman and the victim that appears to be over makeup, but words were exchanged that could be interpreted as hate speech.

Police said the woman bit the male victim in the thigh and threatened to give him AIDS.

No charges had been filed as of Friday.

Last, on Thursday, police said a woman was shot in the buttocks in the 6000 block of Eads St. NE, a well-known center of prostitution. Police and Budd said the victim was transgender. Both said the motive appeared to be robbery.