A grisly discovery is stirring up controversy in the southeast English town of Buckingham.

Sometime during December, developers excavating a grassy tract of land ahead of construction of a new retirement community stumbled upon what appears to be a bizarre cemetery of unknown origin. So far, the team has unearthed 40 skeletons, each with their hands tied behind their backs, buried in shallow graves.

Archaeologists contracted with Brio Retirement Living Holding, the company developing the plot, are keeping mostly mum until an in-depth investigation—slated to take weeks or months—concludes, according to BBC News. But locals are already itching for answers, and tensions in the town remain high, reports Sally Murrer for the Milton Keynes Citizen, the local news site that broke the story last week.

Once home to a now-defunct farm, the land isn’t coughing up much info, either (though the formal dig may soon change that). The skeletons’ contorted, bound positions, as well as the depth of their graves, hint that they were once “prisoners of some kind,” Robin Stuchbury, Buckingham’s district and town councilor, tells the Milton Keynes Citizen.

Beyond speculation, however, the true nature of the burials is currently anyone’s guess. Speaking with BBC News, Buckingham Society historian Ed Grimsdale suggests the bodies may be the remains of people executed more than one thousand years ago, perhaps even during the Anglo-Saxon period, which lasted from 410 to 1066 A.D. If that’s the case, the gruesome discovery could represent “the biggest find of executed prisoners in the whole of the South of England” from this historical era.

Still, says Stuchbury, the skeletons could also be much more recent, perhaps dating to the English Civil War, or to a period when “criminals … were hanged on the gallows in the town.”

In an interview with the Milton Keynes Citizen, representatives from the Buckinghamshire County Archaeological Service (BCAS), a governmental body that provides local city planning services and maintains a historic environment record, explained that they had been made aware of the skeletons, but haven’t been able to investigate the plot themselves. Until they receive a detailed report from the archaeological contractors associated with Brio Retirement, spokespeople have declined to comment on the nature of the remains.

That report has yet to be made public to local officials or Buckingham residents, reports Mindy Weisberger for Live Science. Once released, though, it should contain descriptions of artifacts found in the graves, as well as the ages and biological sexes of the skeletons. Unusual markings on the bones could also reveal how the 42 unfortunate individuals died. BCAS anticipates it could take months for those details to be revealed, according to BBC News.

Depending on what the investigation unearths, the fate of Brio’s planned retirement community, intended to provide 72 homes for residents aged 55 or over, may also be up in the air. The company, however, won’t escape the unexpected twist in their plans without a smidge of irony: Their selection of the West End Farm plot would have put the new development right next to Buckingham’s existing cemetery.