Three people have been charged with first-degree murder in the brutal slaying of a transgender teenager in Houston, Mo., and a fourth has been arrested on other charges.

Ally Steinfeld, 17, was found dead last week in a rural area near a mobile home occupied by one of the suspects, the Associated Press reports. Both local and national media identified Steinfeld by a male name, but The TM Planet, a website focusing on transgender issues, identified her as Ally. She had been stabbed repeatedly, including in the genitals, and her eyes had been gouged out, according to the AP. Her body was burned in an attempt to conceal evidence of the crime.

“It is a grisly terrible series of heinous acts by the accused,” Texas County prosecutor Parke Stevens Jr. told the Houston Herald, a local paper. Steinfeld was apparently killed September 3, six days before her birthday, the paper reports. Her family had reported her missing September 14, having last heard from her September 1.

The accused are Andrew Vrba, and his girlfriend, Isis Schauer, both 18 and Houston residents; they are charged with first-degree murder, armed criminal action, and abandonment of a corpse. Briana Calderas, 24, is charged with first-degree murder and abandonment of a corpse. Steinfeld’s remains were found near Calderas's trailer in Cabool, Mo., about 20 miles from Houston. All were charged last week; Monday a fourth person was charged, James Grigsby, who is accused of abandonment of a corpse and tampering with evidence, Springfield, Mo., TV station KYTV reports. Police said they expect further arrests.

Vrba told police he had tried to kill Steinfeld but did not reveal a motive, according to the AP. The women said he had bragged about the killing. Facebook messages exchanged by the women led police to Steinfeld’s body, the Herald reports.

Ashleigh Boswell, Steinfeld's sister, told Springfield's News-Leader that family members weren't sure if the teen's gender identity was a motive in the slaying. Steinfeld had talked to the family about being transgender and wanting to undergo gender-affirming surgery, she said. She described Steinfeld as "a very loving, outgoing person" who "didn't like conflict whatsoever."

Steinfeld’s Facebook page has been filled with messages of condolence, and a GoFundMe page has been set up to assist the family with funeral expenses. On the GoFundMe page is this message from actress Patricia Arquette, along with a $1,000 pledge: “This donation is honor of Ally. Who was brave enough to live her truth in a very ignorant world. I am praying for your family during this heartbreaking time. May you be surrounded by support and love.” Arquette’s transgender sister, Alexis, died last year of AIDS-related complications; members of the Arquette family have long been staunch LGBT allies.