The Discovery

As Jack stepped into David's room, his brow furrowed immediately. The room was in such disarray that it almost made him wrinkle his nose. Clearly, the room's owner was an extremely messy person. The desk was cluttered with disorganized items, and the air was thick with a musty, neglected scent.

"Everyone, search carefully. Don't leave any corner unchecked," Jack said in a calm tone, directing the officers to conduct a thorough search.

He walked over to the desk and began sifting through the piles of papers. Most of the files were household bills, which was unremarkable. However, when he came across a bill for a large loan, his hand paused slightly. The loan was dated three years ago, and the amount was substantial enough to catch his attention.

He hesitated for a moment, then turned and glanced at Emma, who was standing at the door. He asked softly, "Do you know anything about this loan?"

Emma walked over to the desk, glancing down at the document with obvious hesitation. "I... I know. Before Mom passed, she and Dad argued a lot. I overheard them mention something about a loan, but I'm not sure if this is the one."

Jack pressed on, "Do you know why your family needed to take out such a large loan?"

Emma bit her lip tightly, letting out a sigh, as if trying to recall something. "Dad... he was tricked and lost a lot of money. And he had just lost his job, so we had no income, and we had to take out a loan."

Jack nodded slightly, his mind forming an initial hypothesis. He remained silent for a moment, then continued going through the papers on the desk.

At that moment, the voice of an officer broke the silence in the room. "Detective, there's a box here!"

Jack quickly walked over to see the officer holding a small metal box. The box was old and worn, its surface covered with a thin layer of rust. The lock had no key and appeared to be unopened.

"Keep an eye on the small items," Jack ordered. "Everyone, keep looking to see if we can find the key anywhere."

He moved over to the bookshelf, searching through the disorganized books and clutter, hoping to find the key. After a few moments of rummaging, Jack finally found a rusty key under the mattress.

He took the key and returned to the box. With a soft click, he opened the long-unused metal box. Inside, there was a yellowed family photo, a pair of wedding rings, and an insurance policy.

Jack pulled out the insurance policy and examined it carefully. It was a high-value accident insurance policy, with Sarah Carter listed as the insured and David as the beneficiary. This discovery made Jack's brow furrow even further. The sum of the policy was enormous, and the fact that the beneficiary was the husband of the deceased only added more suspicion to the case.

As he continued to examine the box's contents, Jack's eyes suddenly caught sight of a strand of hair. He frowned and reached for it. The hair was long, clearly not from a man. Jack carefully picked it up with a pair of tweezers, placed it in an evidence bag, and handed it to one of the officers. "Take this for DNA testing. Let's confirm if this is Rachel's hair."

As the officers continued to search, another found some pill bottles. He walked over to Jack and handed them to him. Jack examined the labels, which read "antidepressants" and "mood stabilizers." These were clearly long-term medications. Jack's mind clicked, realizing that David likely had a serious mental health issue, which could explain his violent mood swings.

Jack fell silent for a moment, placing all the evidence carefully on the table. Now, more and more clues pointed toward David. Sarah's drowning was likely not an accident. Perhaps a domestic argument triggered David's manic episode, and in a fit of rage, he accidentally killed his wife and staged the drowning. Or even more likely, he deliberately killed her to collect the large insurance payout.

Whatever the case, David's guilt seemed more and more probable, and Rachel's disappearance was probably linked to him as well.

"Take all the evidence back to the station," Jack ordered the officers in a low, steady voice. "Prepare to interrogate David."