Two men accused of targeting a 78-year-old woman in a gold-bar scam that netted $683,000 will face trial in Lehigh County court, according to Lehigh County District Attorney Gavin P. Holihan.

Jiwan Chen, 57, and Tianhang Zhou, 61, of New York, are charged with financial exploitation of an older adult, criminal use of a communication facility, theft by unlawful taking, theft by deception, receiving stolen property and related conspiracy offenses. Both are being held in Lehigh County Jail under $500,000 bail.

Authorities said a 78-year-old resident of Luther Crest Senior Living was contacted by people claiming to represent American Bank, who falsely told her that her identity and Social Security number had been compromised. After unsuccessful attempts to transfer money into what investigators said was a fraudulent account, the victim was directed to purchase gold bullion and deliver it to couriers.

Police said the woman made four deliveries totaling $550,000 in gold before investigators learned she was preparing to deliver an additional $133,000 in gold July 1. While conducting surveillance, officers observed the victim hand over the gold to Chen outside the senior living facility and identified Zhou in the area in a vehicle, authorities said.

Investigators determined Chen and Zhou worked together to obtain the gold from the victim, police said.

The defendants waived their preliminary hearings Sept. 2. Charges against Zhou were dismissed at the hearing but were refiled Sept. 3, according to the district attorney’s office. Both men are scheduled for formal arraignment Oct. 16 before Lehigh County Judge Robert L. Steinberg.

The case was investigated by South Whitehall Township Police Detective Tyler Doherty and will be prosecuted by Chief Deputy District Attorney Ramma R. Mineo and the district attorney’s Elder Abuse Task Force.