Customs officers arrested the woman at Owen Roberts International Airport on 20 May after she arrived in Grand Cayman on a flight from Miami, Assistant Collector of Customs Trevor Williams said.
She was held on suspicion of importation and possession of an unlicensed firearm and accessories.
“The investigation is ongoing,” said Mr. Williams, adding that officers are looking into whether anyone else is involved and also liaising with authorities in Miami.
According to the Cayman Islands Customs Department, the woman had been selected for her baggage to be X-rayed. During the X-ray of her luggage, an object that appeared to be a firearm part was found.
When customs officers searched her bag, they found firearm parts that, when assembled revealed a completed .45-calibre handgun, along with a gun holster, rifle scope and a firearm cleaning kit.
Mr. Williams said the woman has been released on bail and remains in the Cayman Islands. She has not been charged.
The importation of illegal firearms and ammunition can result in fines of $100,000 and imprisonment for 20 years.