**Chapter 4: A New Lead and a Growing Enigma**

Phryne's eyes widened in surprise as she listened to the museum director on the phone. She couldn't believe that another artifact had gone missing, and she felt a surge of determination to get to the bottom of the case. "What did he say?" Jack asked, noticing her expression. Phryne took a deep breath and repeated the director's words. "The artifact that was stolen is a rare, 18th-century diamond necklace. The director is frantic and wants to meet with us immediately." Jack's face darkened. "This changes everything. We need to get to the museum and assess the situation." Phryne nodded, already thinking about the implications. "I think we should also review the security footage from the museum to see if we can spot any similarities with the previous theft." As they arrived at the museum, Phryne could see that the director was indeed frantic. He was pacing back and forth in his office, his face red with worry. "Thank goodness you're here," he exclaimed, rushing over to Phryne. "We've been robbed again. The necklace is gone, and I have no idea how it happened." Phryne smiled reassuringly. "Don't worry, we'll do everything we can to catch the thief and recover the necklace." Jack began questioning the museum staff, while Phryne took a closer look at the display case where the necklace had been kept. She noticed that the case had been opened using a duplicate key, and she made a mental note to ask the director about the key's whereabouts. As they continued to investigate, Phryne couldn't shake the feeling that they were dealing with a more sophisticated thief than they had initially thought. The fact that the thief had been able to steal two valuable artifacts in a short period of time suggested a level of planning and expertise that was unsettling. Just as they were finishing up their investigation, Phryne's phone rang again. This time, it was an anonymous caller, and the voice on the other end sent a shiver down her spine. "You'll never catch me," the voice said, before hanging up. Phryne's eyes locked onto Jack's, and she could see the concern etched on his face. They were in for a long and challenging investigation, and Phryne was determined to solve the case and bring the thief to justice.