WEST PALM BEACH, Fla. — The Chinese woman who was arrested after gaining entry to President Trump’s private club while carrying four cellphones and other electronic equipment had stored even more electronics in her hotel room, including a device used to detect hidden cameras, a federal prosecutor said Monday.

The woman, Yujing Zhang, 32, was arrested March 30 after telling Secret Service agents that she had come to use the pool at Mar-a-Lago and showing two Chinese passports. After the authorities determined that the event she said she had come to attend did not exist, she was arrested and charged with lying to a federal officer and accessing a restricted area.

Ms. Zhang had entered the property with four cellphones, a hard drive and a thumb drive infected with malware, according to federal court records. Upon searching her hotel room, investigators found another cellphone and a radio frequency device that detects hidden cameras, Assistant United States Attorney Rolando Garcia said.

She also had nine U.S.B. drives and five SIM cards in her room at the Colony Hotel, along with several debit cards and about $8,000 in cash, including about $700 in Chinese currency, Mr. Garcia said during a bond hearing at the U.S. District Court in West Palm Beach.