At first, authorities suspected an injured prisoner had fallen in the Oconee Detention Center. Now they think someone assaulted Joshua Charles Campbell, and the Walhalla police are investigating. Chief Ronald Wilbanks said, as part of his department’s investigation, police officers last night were planning to question other inmates as to what happened and why. At this point, Wilbanks said the investigation can’t rule out jail overcrowding as a potential contributing factor. Detention Center officials say the incident was discovered early Tuesday evening. An Oconee ambulance transported Campbell to a Greenville hospital. Campbell is a patient there. According to Sheriff’s spokesman Jimmy Watt, Campbell was being held in the Oconee Jail after his arrest on charges of burglary and larceny.