The York County coroner's office said an autopsy Thursday wasn't able to conclude what caused 28-year-old James Earl Greer Jr.'s death.
County prison officials said Greer was found unresponsive in his cell around 3 a.m. Tuesday. He was facing charges in the Dec. 7 strangling death of his ex-girlfriend, 32-year-old Heather Marie Bechtel, in Lower Paxton Township.
Toxicology tests are being performed. It may take several months to get the results.
Authorities alleged that after killing Bechtel in her apartment, Greer tried unsuccessfully to poison himself with household cleaning solutions. He was treated at a local hospital and returned to police custody.