8 Serial killers who were never captured

For whatever reason, there's something about serial killers that fascinates us. There's a reason that true crime documentaries and movies based on real-life serial murders are so successful - and that's because we're all watching. Usually, there is at least some comfort in knowing that eventually the killer in question was arrested and brought to justice, but that isn't always the case.

In fact, just as many homicides go unsolved, there are some serial murders whose culprit the police never managed to catch. Check out this list of the serial killers that were never caught, if you've got no problem with a sleepless night...

1. The Servant Girl Annihilator

Operating between 1884 and 1885 in Austin, Texas, an axe-wielding maniac killed seven women and one man, with six women and two men surviving attacks. At the dead of night, the killer would drag his victims out of their home before killing them.

In 1885, the New York Times claimed that up to 400 men were interrogated in connection to the attacks, but no one was charged. There are plenty of unsubstantiated theories about the identity of the killer, including some who believe that Jack the Ripper honed his craft in the US before his famous murders in London a few years later.

2. The Zodiac Killer

This serial killer claimed to be responsible for 37 murders over the 60s and 70s in Northern California, but investigators only confirmed 7 victims. He attacked a cab driver and three different couples, with two men surviving the attacks. He made a name for himself after he toyed with the authorities by sending letters and cryptograms to the press, daring the public to crack the codes to find him.

According to one of these decoded messages, he killed in order to 'collect slaves for the afterlife'. Many have obsessed over these murders, with many claiming to have solved the case, but there has been no confirmation, and some of the key suspects have since passed away.

3. Freeway Phantom

In Northeast Washington DC between 1971 and 1972, six black women between the ages of 10 and 18 were murdered. Each one was abducted while on their way home, raped and strangled to death, before their bodies were dumped along the highway.

The second-to-last victim was found with a note that was signed by the 'Free-way Phantom'. "This is tantamount to my insensitivity to people especially women," the note read. "I will admit the others when you catch me if you can!" The police had their suspects, including a gang operating in the area, but no convictions were made. Years later, the case files were lost, making the case nearly impossible to solve today.

4. Alphabet Murders

Also in the early 1970s, three women were raped and strangled around Rochester, New York. Each girl's name was alliterative, and their bodies found in towns which started with the same letter as their names. Carmen Colon was found in Churchville, Michelle Maenza in Macedon, and Wanda Walkowicz in Webster.

A man named Joseph Naso did commit similar murders, but his DNA did not match that which was found at the crime scene, so the case remains unsolved.

5. The Babysitter

Also known as The Oakland County Child killer, this murderer took the lives of at least four children in Michigan in the late 70s. He received the name because each of his victims were discovered fully-clothed and bathed, killed after being held anywhere between four to 19 days. There were some promising leads, including one witness who saw a man talking to a victim the night of the murder, but the case remains open.

6. Colonial Parkway Murderer

In the late 80s, three couples were found dead in their cars along the Colonial Parkway in Virginia, while a fourth couple went missing in the area and are presumed dead too. There are many theories about the case, including one that the culprit was a police officer who could pull over their victims, but nothing conclusive.

7. Highway of Tears Murders

Many people have disappeared on Highway 16 in British Columbia, with 16 to 40 of the victims potentially being killed by the same person. The frequency of the murders suggested one killer, but the large stretch of time (1969-2011) suggests more than one. Many of the victims were First Nations women, leading locals to assume that racism played a part in both the attacks and the lack of progress in each case.

Royal Canadian police suspected Bobby Jack Fowler was responsible for 10 to 20 of the victims, while Canadian serial killer Cody Legebokoff was convicted of one of them. However, that still leads dozens more unsolved cases on that highway.

8. The Craigslist Ripper

Also known as 'LISK,' this killer is responsible for the deaths of between 10 and 16 women in Long Island, New York, between 1996 and 2011. Many of the victims were sex workers who advertised their services on Craigslist, leading authorities to believe that the killer arranged to meet up with them, before raping and killing them, then dumping their bodies along the Ocean Parkway.

A key suspect was James Burke, the former police chief of Suffolk County, who had previously used the services of one of the victims. Burke had obstructed an FBI probe into the case during his time as the police chief, but was only convicted of obstruction.

With important physical files no longer needed, and with more advanced technology at their disposal, there is less chance of serial killers of this magnitude getting away with it in quite the same way. But I'm betting that won't make it any easier to get to sleep tonight.