Last month, a heavy machinery operator working for the Fort Bend Independent School District was excavating dirt on the site of the district’s new career center in Sugar Land when he made an unexpected discovery: a human bone. Police called to the scene soon determined that the remains were old enough to rule out the possibility of a recent crime, so Fort Bend ISD notified the Texas Historical Commission that they had stumbled across a previously unknown historic cemetery.

To Reginald Moore, the discovery was no surprise. The retiree and activist, who lives just outside Sugar Land, has been warning Fort Bend ISD that there may be unmarked graves on the site since the district bought the land from the Texas Department of Criminal Justice in 2011. Moore became interested in the history of convict labor in Fort Bend County while working as a prison guard in the 1980s at the Jester Unit in nearby Richmond. As he discovered, much of modern Sugar Land was once a notorious slave plantation dedicated to harvesting and boiling down sugar cane. After the abolition of slavery in 1865, the plantation owners began “leasing” convicts from state prisons to replace their lost slaves. Historians have called the convict lease system, which was widespread across the South after the Civil War, “slavery by another name.”

In the first decade of the twentieth century the land was purchased by the recently incorporated Imperial Sugar Company, which founded the company town of Sugar Land. Convict leasing was outlawed by the state in 1910, but in practice this simply meant the convicts would work for the state rather than private industry; in 1908, the state bought a 5,235-acre tract from Imperial Sugar and established the Imperial Farm prison, later known as the Central Unit, where prisoners continued to perform agricultural labor until the state closed the prison in 2011.

Moore believes the bodies discovered by Fort Bend ISD are either slaves or convict laborers. It’s not an unreasonable guess—after all, it’s just half a mile away from the Old Imperial Farm Cemetery, a small graveyard for inmates of the Central Unit. The several dozen tombstones each bear a name and inmate number (“Fred Carson, number 29760, died in 1917 at the age of 28”). In 2010 Moore was appointed caretaker of the cemetery by the Texas Historical Commission because of his extensive historical research on the site.

“I always had a feeling something was there,” Moore says. He received a call from Fort Bend ISD superintendent Charles Dupre on April 6 alerting him to the discovery, but his attempts to visit the site have been rebuffed. “They won’t even let me see it, and that hurts me so bad. All that work I’ve done, and they ran me off.”

A spokesperson for Fort Bend ISD, Veronica Sopher, confirmed that the superintendent had called Moore and that he had been barred from the property because it’s an active construction site. (Although construction has halted around the cemetery, it continues on another part of the property.) Sopher says the district has hired an archeological consulting firm to study the cemetery and determine what steps to take. So far they’ve discovered at least 30 bodies. Under the state’s Antiquities Code, if the district wants to continue building on the site it will need to disinter and re-bury the bodies in a perpetual care facility. That requires authorization from a judge and a permit from the Texas Historical Commission.

“It’s not uncommon to find bones at a construction site,” says Chris Florance, a spokesperson for the historical commission. “There have been humans living in Texas for thousands of years, and you find evidence of that habitation everywhere, so it’s not uncommon to find an unknown burial.”

University of Houston anthropologist Ken Brown, who has consulted with Moore, believes Fort Bend ISD should have conducted more research before starting construction on the new building. “Given how much Reggie has been talking to people over the last 20, 25 years, I can’t believe they didn’t do something archeological to start with,” he says. Sopher, the Fort Bend ISD spokesperson, says the district received a permit from the Texas Historical Commision before it started work and that “all appropriate measures were taken.”

Although the bodies have not been conclusively dated or identified, Brown says he wouldn’t be surprised if it was an African-American cemetery. “When you have plantations where you have African-American cemeteries, they’re not marked in the same way as European-American cemeteries. They’re not recorded as well, and they have a tendency to be either removed from the ground or simply built over.”

For his part, Moore wants the district to stop construction and preserve the newly discovered cemetery in place. If it insists on moving the bodies, he would like them to be reburied near the Old Imperial Farm Cemetery that he currently oversees.

“That would be a sad thing if they disinter those graves and remove them like that,” he says. “They’ve disrespected these people so much, and they’re trying to disrespect them again.”