A brother and sister have been charged in federal court in connection with an explosive device found at MacDill Air Force Base in Tampa, Florida, according to court documents released Wednesday.

Alen Zheng, 20, and Ann Mary Zheng, 27, were charged in separate federal indictments. Alen Zheng faces charges of attempting to damage government property, unlawfully making a destructive device, and possessing an unregistered destructive device. His sister Ann Mary Zheng is charged with witness tampering and being an accessory after the fact.

The charges stem from a suspicious package discovered outside MacDill Air Force Base on March 16. The FBI investigated the device, which was described as an improvised explosive device found near the visitors center at the base. A video later surfaced claiming responsibility for the possible explosive device, prompting further FBI investigation.

Ann Mary Zheng is currently in custody, while her brother has fled to China, according to FBI Director Kash Patel's social media post. Online court records did not list attorneys for either defendant.

MacDill Air Force Base houses the U.S. Central Command, which oversees American military operations in the Middle East, Central Asia, and parts of South Asia. The base has been on heightened alert since the start of the war in Iran.

Separately, another individual was arrested earlier this week for making threatening phone calls to the base following the discovery of the device. Investigators have not established any connection between that caller and the Zheng siblings.