Brother and sister charged after an explosive device was found outside MacDill Air Force Base

TAMPA, Fla. – A Florida man accused of planting an explosive device outside MacDill Air Force Base has fled to China, while his sister is now in custody after both were charged in connection with the incident, federal officials announced Wednesday.

According to the Federal Bureau of Investigation, Alen Zheng, 20, faces multiple federal charges, including attempting to damage government property, unlawfully making a destructive device and possessing an unregistered destructive device. His sister, Ann Mary Zheng, 27, was booked on charges of witness tampering and acting as an accessory after the fact.

What we know:

The United States attorney’s office says the investigation began on March 10, when a 911 call warned of a bomb near the base’s visitor center. At the time, no device had been located.

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Six days later, on March 16, an Air Force service member discovered a hidden explosive device near the visitor center. Investigators later determined it was an improvised explosive device capable of causing serious harm or death.

Dig deeper:

According to federal prosecutors, Alen Zheng purchased the phone used to make the threat at a Best Buy, and surveillance video captured him making the purchase and using a vehicle later tied to the case.

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Investigators say Alen Zheng and Ann Mary Zheng quickly made plans to leave the country. The day after the bomb threat, the pair allegedly sold the vehicle used to transport the device to CarMax and booked flights to China.

They both left for China by March 12, officials said.

Ann Mary Zheng later returned to the U.S. and was stopped in Detroit, Mich., on March 17. Authorities allege she helped her brother escape and tried to get rid of evidence tied to the investigation.

Courtesy: Pinellas County Sheriff’s Office

During a search of Alen Zheng’s Land O’Lakes home, investigators said they found items consistent with those used to build the explosive device. Traces of explosive residue were also reportedly found in the vehicle the pair sold.

Authorities also confirmed no charges have been filed against the suspects’ mother, though she is currently in custody for deportation proceedings.

The case is part of a federal investigation that also led to charges against another individual, identified as Jonathan James Elder, 35, who is accused of making threatening phone calls to the base days after the device was discovered. 

What we don’t know:

Officials say the Zhengs’ motive remains unknown, and it is unclear why the device did not detonate. 

What they’re saying:

“We are exploring every avenue to get [Alen] Zheng back to the United States,” U.S. Attorney Gregory Kehoe said during a press conference Thursday.

The Associated Press contributed to this report.