At age 14, Michael Hernandez lured a boy from his middle school into the bathroom and stabbed him 40 times, resulting in the death of the young boy. After the stabbing, he calmly attended class. Upon further investigation, authorities found a list with the names of Hernandez’ planned victims. His sister was on the list as well. He was given a life sentence in 2004, which the US Supreme Court mandated a review for recently.

Brian Blackwell from Liverpool, England, was 18-years-old when he took out several loans and credit cards in his father’s name, wanting to appear richer and wanting to live a lavish lifestyle. When his parents started asking questions about the money, he beat them with a hammer and stabbed them repeatedly. He then took a trip to New York with his girlfriend, leaving his dead parents in the house. Authorities found their decomposing bodies. Blackwell was diagnosed with narcissistic personality and he was sentenced to life in prison.

In 1995, Bryan, then 17, and his brother David, then 15, killed their own family in Pennsylvania. They savagely stabbed their mother after stuffing shorts in her mouth. After killing their mother, they moved upstairs where they beat their father and 11-year-old brother to death in their sleep. Bryan and David were both Neo-Nazis. They shaved their heads, wore military uniforms and got tattoos across their foreheads. They were both sentenced to life for the murder of their family.

In 1964, Edmund Kemper shot both his grandparents. He was only 15-years-old. During questioning, he said that he wanted to see what it would feel like to kill Grandma, and that then he killed Grandpa because he’d be angry about Grandma being dead. He only served five years for the shootings. When he was released, he went on to kill and dismember six female hitchhikers in Santa Cruz. He later also killed his mother and her friend, and then turned himself in. By then, he was known as the Co-Ed Butcher. Because of his size and intelligence (he was 6 ft 9, weighed over 300 lbs and had an IQ in the 140 range), his victims always stood very little chance. Although Kemper was sentenced to life, he requested to be executed. Capital punishment was suspended at that time, so Kemper is still serving his life sentence.

In 1993, two-year-old James Bulger was abducted from a mall in Bootle, England. Ten-year-olds Jon Venables and Robert Thompson weren’t only responsible for the little boy’s kidnapping, but also for his brutal murder, torture and mutilation. They led the boy through a 2.5 mile walk through Liverpool. They dropped him on his head, leading to injuries to his face. Thirty-eight people saw the three boys on their walk, but no one called the police, assuming the two boys were with their younger brother. They led James to a railway line and began torturing him. They poured paint into the boy’s eyes, kicked and stomped him, and threw bricks and stones at him. They put batteries in his mouth and finally, a 22-pound bar was thrown on top of him, fracturing his skull. James suffered so many injuries – 42 in total – that it was never determined which one was fatal. Before leaving James behind, Jon and Robert laid him across the tracks and covered his head in rubble, hoping a train would hit him and make his death look like an accident. His body was, in fact, cut in half by a train. The two boys were arrested after one of them was recognized on CCTV footage of the mall, and they were imprisoned until they were 18, making them the youngest convicted murderers ever. They were released on parole under new identities.

Michael Carneal wrapped a shotgun and a rifle in a blanket and took them to school at age 14. He passed off the weapons as an art project he was working on. He also carried a loaded pistol in his backpack. He opened fire on a prayer group. The attack killed three girls and injured five more people. He then turned the gun on himself and said “Kill me please, I can’t believe I did that.” After being diagnosed as mentally ill, he was incarcerated and is currently serving a life sentence.

In November 1998, an eight-year-old girl named Maddie Clifton disappeared. Volunteers searched for her for a week, but the search was called off when Josh Phillips’ mother went to clean his room and found Maddie’s body under his bed. Phillips was 14 at the time of Maddie’s murder and was sentenced to life in prison without parole.

Spencer was the mastermind behind a San Diego school shooting in 1979. She lived across the street from the school and shot students and teachers from her bedroom window. She was only 16-years-old, but she was tried in court as an adult. She’s currently still in prison.

Graham Young was an English serial killer, who killed his victims through poison. He was sent to a mental hospital when he was only 15, after trying to poison his own family and kids at school, which made them all violently ill. He never got caught until he killed his stepmother by putting poison in her tea. He spent nine years in a mental hospital, and after his release, he poisoned another 70 people, two of whom died. Young, also known as the Teacup Poisoner, died of a heart attack in prison in 1990.

Mary Bell strangled two toddlers at the age of 11 in England. She carved the letter M into their chests and mutilated their bodies. Coming from an abusive family, Bell showed clear signs of a psychopath and was sent to prison. Twelve years later, she was released and given a new identity. She had a daughter, and in 1998, they had to flee their house under bedsheets because the press found them. In 2009, Mary became a grandmother.

Paul Gingerich helped his friend Colt Lundy kill his stepfather at the age of 12. Gingerich, Lundy and another friend wanted to run away to Arizona, but Lundy feared his stepfather would try to stop them. So he convinced his two friends to assist in the murder of his stepfather. The other boy pulled out just before the murder, but Lundy convinced Gingerich to partake. They shot him in the chest four times. He was sentenced to 30 years in prison. He’s currently 17-years-old and has the possibility to be released on parole at the age of 18.

Eric Smith was only 13-years-old when he was biking to summer camp, and lured four-year-old Derrick Robie into the woods. He strangled the boy and smashed his head in with a rock. He was convicted of second-degree murder in 1994 and sentenced to the maximum term that was available for juveniles at that time, which was minimum nine years to life. In his parole hearing in 2014, Smith said he was being bullied by his family at the time and took out his frustrations on Robie. After he strangled him, he was afraid Robie would tell, so he killed him.

Alyssa Bustamante suffered from depression at a young age and tried committing suicide. She played dangerous pranks on her siblings and expressed that she wanted to kill her two younger brothers. Instead of killing her brothers, she killed nine-year-old Elizabeth Olten. She strangled the little girl, then slit her throat. She then buried her body in a shallow grave she had dug in the woods half a mile from her house. She was sentenced to life in prison with the possibility of parole.

In 1988, David Brom murdered his family inside their home in Minnesota. He was only 16 at the time. He’d gotten into an argument with his father the night before and early the next morning, he hit him repeatedly in the head with an axe. He killed his mother and his brother next. When he spotted his sister, standing over their mother’s body upstairs, he killed her too. He left their bodies and his axe and went to school. At school, he bragged about murdering his family to a friend. When the rumor started spreading around the school, someone alerted the authorities, and they found all four bodies inside their home. David Brom was given three life sentences. He’s eligible for release in 2041.

At age 15, Kipland Kinkel was expelled for bringing a gun to school. He returned to school the next day with a rifle and opened fire in the cafeteria. He killed two students and injured 25 others. He then tried to attack the police with a knife, telling them he wanted to die. When the authorities raided his house, they found both his parents at the house, dead. He had shot them in the head and the house was rigged with explosives. Apparently, the son and his father started arguing after his father said he would send him to military school if he didn’t start behaving better. They also found a note on the kitchen table which said “My head just doesn’t work right. God damn these voices in my head… I have to kill people.” Kinkel is currently serving a 111-year sentence with no chance of parole.