A fourth defendant in a drug-selling ring entered a guilty plea in Carbon County court on Thursday and is facing a state prison term.

Robert David Rex, 59, of Lansford, pleaded to one count each of corrupt organization, criminal conspiracy to possession with intent to deliver a controlled substance and possession with intent to deliver a controlled substance. The illegal substance is methamphetamine.Rex was one of seven rounded up on June 10, 2016 and charged with operating a crystal methamphetamine ring in Carbon and Lehigh counties.Arrested with him were Edilberto Ortiz Jr., 45, ofWest Tilghman Street, Allentown; Holly Ann Eckhart, 50, of Palmerton; Richard E. Moyer, 57, of Lehighton; Connie Serfass, 60, of Lehighton; Donna Marie Ziegenfuss, 54, of Palmerton; and Susan Rex, 57, of Nesquehoning.Serfass, Moyer and Susan Rex have previously pleaded in the case.Judge Steven R. Serfass, who accepted the pleas, told Rex he faces a minimum prison term of between 18 and 24 months up to 10 years in the standard range, which would be a state term.According to criminal complaints filed by the attorney general's office in support of the charges, investigators identified Ortiz as a main distributor who supplied six people with methamphetamine. Those people later redistributed the drugs to their customers.Officials said the activity occurred between January and March 2016.Investigators used confidential informants for controlled purchases of methamphetamine over the course of the investigation.More than 4 pounds of methamphetamine were seized from a residence where Ortiz was staying, investigators reported in a criminal complaint.That search also resulted in the seizure of a .32-caliber handgun, roughly $2,400 in cash and drug paraphernalia.Searches of other residences resulted in the seizure of various quantities of methamphetamine, cash, digital scales and drug paraphernalia.Serfass deferred sentencing and ordered the adult probation office to prepare a presentence investigation report.