1Mack Ray Edwards
Mack Ray Edwards was a serial killer who worked for CalTrans. He'd kill his victims and then bury the bodies in places he would later help build the highways over. Not all his victims have been found, and many are very likely still under some of the California highways you may have driven over countless times.
The serial killer Bela Kiss liked to pickle people in barrels stored in his basement. Someone figured it out but they couldn't get him because he was fighting in World War 1. By the time they tracked him down, he had disappeared and left a dead guy in his hospital bed. He supposedly joined the French Foreign Legion and deserted that too, with the exception of one possible sighting as a janitor in New York. The janitor disappeared before anyone could confirm it.
The Hillside Stranglers picked up a young woman to murder. Then they discovered that her father was Peter Lorre, a legendary Hollywood character actor. They let her go because they feared that killing a celebrity's daughter would bring too much attention down.
4Golden state killer
The golden state killer, known at the time as the east area rapist, would often break into the homes of couples, making the woman tie up the man. He would stack dishes on the back of the man and threaten that if he heard the dishes fall, he would kill everyone in the house, then he would rape the woman repeatedly and ransack the house for hours. At a community meeting about the rapist, a macho man stood up and went on a rant about how a real man would never let such a thing happen to him or his wife. The rapist proceeded to attack that man and his wife soon after, meaning he was attending the community meeting about himself.
Jeffrey Dahmer towards the end right before he got caught, had so many bodies in his apartment that he ran out of the room and stored one victim in his bathtub. He proceeded to shower over him every day for a month. He didn't eat people with tattoos because he said the ink made the flesh taste weird. He gave sandwiches to the people in his apartment building that could've possibly been made from his victims’ flesh.
6Pee Wee Gaskins
Pee Wee Gaskins, the most prolific serial killer in South Carolina drove around in a hearse with a bumper sticker that read "WE HAUL ANYTHING, LIVING OR DEAD." He told people that he needed it to take the bodies of people he killed to his private cemetery. He claimed to have killed between 100 and 110 people.
American serial killer Richard Kuklinski killed a man and left his body in an oil drum outside of a diner just to see how long it would take for someone to investigate. He would order sandwiches from the place and sit on the drum while he ate. He also made a clicking noise with his mouth when he was angry. If you heard that, you were as good as dead. He claims to be responsible for a string of homeless murders in a specific neighborhood, killed a cop for beating him in the pool, and shot a man with a crossbow just to test it out for an upcoming hit.
8Mark Brandon Read
Mark Brandon "Chopper" Read was a renowned killer in Australia. However, he only targeted drug dealers and people who made attempts on his life. When he got old he was told he had liver cancer and had only a few weeks to live. He was asked by the television show 60 minutes Australia if he wanted one last interview before he died. He accepted. When asked about all the murderers, which he previously claimed as self-defense, not him or he covered them up, he just confessed to all of them, claiming they were never self-defense and he had committed the ones he previously denied. Then he passed away a few weeks later. He went out listing everyone he killed. It shocked everyone.
9John Norman Collins
John Norman Collins used to pick up women on his motorcycle. The bodies of his victims (women) used to be dumped here and there but they were always washed. Turns out he only killed women who were on their period. Also, he was referred to as John Norman Collins during his trial (he later changed his last name to Chapman) because there was a lawyer in town whose name was John Collins and this was a way to distinguish between them.
Brazilian serial killer "little Petey" murdered over 40 people in prison. He began by murdering the gang that killed his girlfriend and then stabbing his father, who was in prison for killing his mother, during a visit. He was well liked because he was considered a sort of vigilante avenger, despite killing indiscriminately within the prison. Because of Brazil's odd sentencing laws, he could only serve a maximum of 30 years and is currently a YouTuber.