With today's technology, committing a "perfect crime" is becoming increasingly difficult. Very few cases have left us with so many questions and so many "what if?" Even the best detectives struggled to figure out the answers to these 4 creepy, unsolved mysteries. Where are Sherlock Holmes and Dr. Watson with their impeccable mystery solving abilities when we need them?

1. The enigmatic case of Elisa Lam.

Elisa Lam was a 21-year-old Canadian student who went missing at the end of January in Los Angeles. Nobody knew she was dead until the hotel guests started complaining about the water having an odd taste. When the hotel workers went to the water tank to check it out, they discovered Lam's body. The creepiest part is that nobody knows how she got up to the roof and the surveillance footage of Elisa shows her acting very strange, almost as if she was possessed. Strangely, her autopsy showed no signs of drug or alcohol use.

2. The spooky case of the Somerton man

The Somerton man was found washed up on a beach, wearing a suit, carrying no ID and showing no signs of a struggle. The only clue he had on his body was a piece of scrap paper that said "Tamam Shud" meaning "it is finished" in Persian. The book that it comes from is very rare and was found just a few blocks away with a secret message only seen with UV light. Many people believe he was, in fact, a spy and committed suicide with a poison that left his body quickly. Since the day he washed up in Australia on November 1948, the case has been reopened many times in order to figure out what exactly happened to him.

3. The baffling case of Bella and the witch elm

On April 18, 1943, some young boys found a human skull in the hollow of a tree. As police started to investigate the case, they found more human bones and pieces of clothing that seemed to belong to a woman. There was also a piece of taffeta lodged in the mouth leading experts to believe she was asphyxiated. Several months passed and nobody could identify the woman from the elm tree, and soon, graffiti started popping up everywhere asking the same question, "who put Bella in the witch elm?" Although many theories have popped up about who the woman could be, nobody has an actual clue who 'Bella' is and why she was found in the tree.

4. The frightening case of the Zodiac Killer

The self-proclaimed zodiac killer was linked to at least five different grotesque murders in Northern California in 1968 and 1969. He was famous for taunting and threatening police with multiple letters as well as reaching out to local newspapers to 'speak' to the officers. Around 1974 however, the communication abruptly stopped and nobody was arrested for the murders. The case remains open and has sparked lots of public interest, leading to multiple theories and stories being written about who the killer might be.