Three young Black girls were strangled and left in a pond last summer in east Texas, and no arrests have been made in a case that advocates and experts believe has been severely mishandled by local authorities.

Nine-year old Zi’Ariel Robinson-Oliver, 8-year-old A’Miyah Hughes, and 5-year-old Te’Mari Robinson-Oliver, known as the Oliver 3, were reported missing on July 28, 2022, in Atlanta, Texas. The girls’ cousin, Paris Propps, who was watching the three sisters and their siblings while their mother was at work, reported the girls missing around 9 p.m. Hours later, on July 29, all three bodies were found in a nearby pond.

Initially, authorities said it was a drowning. But in March, nearly eight months after the girls were last seen alive, the Cass County District Attorney’s Office said in a statement that a homicide investigation is underway.“Autopsy reports concluded the manner of death for all three girls was homicide, indicating evidence of strangulation. The girls also suffered lacerations to their faces,” the press release obtained by Yahoo News from the Cass County District Attorney’s Office said.

Now advocates are stepping in to demand answers. On April 3, Minister Quanell X, the leader of the New Black Panther Nation, traveled four hours from Houston to hold a press conference in Cass County and demanded that the FBI and Department of Justice step in to investigate. The FBI has not responded to a request for comment from Yahoo News.

Quanell X stood beside the mother of the Oliver sisters during the press conference. “She was told that they drowned, but she always had a suspicious feeling that the girls did not drown. Well, her suspicions were confirmed by the autopsies,” Quanell told Yahoo News.

The Cass County District Attorney’s Office is currently working with the Texas Rangers and the sheriff’s office to investigate the murders. “Multiple witness statements have been obtained, DNA testing is ongoing, and the investigation will continue,” according to a statement obtained by Yahoo News from the district attorney’s office. Yahoo News contacted the office for additional information but a spokesperson declined to provide more details.

According to U.S. Census data from 2022, Cass County has a population of 28,539 people, and advocates say the town does not have enough resources to investigate three homicides.

“They were presumed drowned because of a sham investigation, a lazy investigation by investigators who obviously didn’t have the resources, the training that was necessary to properly address an investigative crime scene,” Quanell said.

Investigators are still searching for suspects, but experts say the months-long time lapse could have been avoided.

“The usual time frame [for autopsies] depends, I would say within two weeks,” David Thomas, professor of forensic studies at Florida Gulf Coast University, told Yahoo News.

But for small towns, “they send those autopsies off to a whole different county, hours away from that county to do the autopsy,” Quanell said.

However, the autopsy reports are just one piece of the puzzle. Thomas says more could have been done at the time investigators found the girls in the pond.