The detective arrived at dawn. Rain fell on empty streets. A body lay inside. The victim was wealthy businessman. Blood stained the Persian carpet. No weapons were found nearby. The room showed no struggle. Windows were locked from inside. A note lay on table. Detective Wilson knelt beside body. "What time was death?" he asked. Medical examiner checked her watch. "Approximately midnight," she replied. "Any signs of forced entry?" "None," she said quietly. "This killer knew our victim." Wilson stood up slowly. "Who found the body?" "The maid came this morning." "She's waiting in the kitchen." "I'll need to speak with her." The room grew colder suddenly. Wilson felt a shiver. Something wasn't right here. He looked around carefully. A small detail caught attention. A single red thread. It didn't belong there. Wilson picked it up. The killer had made mistake.