In 2015, the remains of four people were found behind a Connecticut strip mall. It was the same desolate stretch of land where investigators had discovered three other bodies back in 2007. Investigators believe that the deaths were the work of one individual – William Devin Howell, a drifter already in jail for the death of Nilsa Arizmendia, who was last seen getting into a van in 2003. Her blood was later discovered in Howell's 1985 Ford Econoline that he allegedly called his "murder mobile." It's there that he allegedly slept next to the body of at least one of his victims. Police were lead to Howell after his cellmate told them about his "garden" where he buried his victims who all disappeared in 2003, when Howell was working odd jobs in the New Britain, Connecticut area. Howell pleaded guilty to the manslaughter of Arizmendia in 2007, and is currently serving 15 years in prison. The trial for the six other murders may not happen until sometime in 2018, as the state continues to process the gruesome evidence. 

A murderer was on the loose in Brooklyn, killing shopkeepers of Middle-Eastern descent while they worked. Police eventually found their man – Salvatore Perrone, a failing business owner whose wife and children had left him. Police say Perrone stalked the streets of Brooklyn with a "kill kit" he carried around in a black duffle bag that included screwdrivers, switchblades, a bloody eight-inch serrated knife, three ladies' blouses, latex gloves, bleach, wire cutters, and a loaded, sawed-off rifle. When they searched his home they found a basement lair filled with ammo, a 12-gauge shotgun and duct tape. It took the jury less than 30 minutes to convict Perrone – nicknamed "Son of Sal" – of killing three Brooklyn shopkeepers. He was sentenced to the maximum sentence, 75 years to life in prison. 

In 2011, Israel Keyes, a former soldier who was honorably discharged from the U.S. Army, turned off his cell phone, boarded a plane to Chicago, and then drove a rental car all the way to Vermont, paying cash for all his expenses to avoid leaving a trail. There, he dug up a "murder kit" that he had buried in 2009 and, supplies in hand, he picked a couple at random and brutally and meticulously murdered them. In 2012, in Anchorage, Alaska, he murdered 18-year-old Samantha Koenig and tormented her family with texts, photographs and debit card withdrawals, pretending she was still alive. He was eventually caught in Texas and sent to Alaska for trial on charges of rape, kidnapping, and murder. He confessed to murdering four individuals in Washington state as well as one in New York  and is suspected of more crimes. Keyes committed suicide in his jail cell before he could be convicted. 

The bodies of Shirellda Terry, Angela Deskins, and Shetisha Sheeley were found wrapped in garbage bags in the East Cleveland neighborhood of Glenville in July 2013. All three had been tortured, mutilated and strangled, and at least one was raped, authorities determined. The bodies were found in close proximity to the home of registered sex offender Michael Madison, who had been convicted in 2002 of attempted rape, according to the Associated Press. Madison was arrested and confessed, never expressing remorse for his crimes. When he appeared in court, Madison apparently taunted and smiled at the victims' families. It was too much for one of his victim's fathers, Van Terry, who attacked him from the witness stand. "I guess we are supposed to find it in our hearts to forgive this clown," Terry said in a video that went viral. That's when the grieving father noticed Madison smirking at him and he snapped, lunging across the courtroom to attack the convict. Madison was sentenced to death for the murders.

Police in Phoenix, Arizona are on the hunt for a serial killer who has slain seven people and injured two, blasting his victims with a semi-automatic shotgun. He apparently picks his victims at random – victims have been male and female, young and old – but he seems to have targeted the predominately Latino Maryvale neighborhood. His first victim was a 16-year-old boy, wounded as he walked the city streets on March 17, 2016. The next night he shot a 21-year-old. In June, the shooter fired over 30 times at the car where 12-year-old Maleah Ellis, her mom Stefanie, and family friend Angela Linner were sitting outside their home, killing them all. Police have no leads, other than a vague description of a suspect as a "light-skinned Latino or white man in his 20s," according to CNN. Authorities are offering a $30,000 reward to anyone who provides information that leads to the arrest and conviction of the killer. 

Between 1985 and 2007, Lonnie David Franklin Jr. may have killed 25 women and possibly dozens, even hundreds, more. He's known as "The Grim Sleeper" for taking a 14-year break from his murder spree, from 1988 to 2002 – though it looks like he might not have "slept" at all. Either way, unlike his more infamous peers like the Hillside Strangler or the Nightstalker, Franklin largely operated outside the media spotlight by targeting women on the fringes of society, including drug addicts and prostitutes, often dumping their naked bodies in alleys or on the side of the road. According to the Los Angeles Times, when police searched Franklin’s home in 2010, they found even more pictures of women, naked with their eyes closed, implying that the scope of Franklin's horrendous crime spree could be much larger than previously thought. Franklin was convicted of the murders of 10 women and sentenced to death in June of this year.

The small town of Chillicothe, Ohio has been haunted by the disappearance of six women, many of whom were mothers of small children. Charlotte Trego, a young mother of two, was the first to disappear. She has not been seen since her mother dropped her off at her apartment in early May 2014. A year later, 26-year-old Tiffany Sayre was on her way to the Chillicothe Inn when she disappeared. Her body was discovered wrapped in a sheet in a culvert in a nearby county. Six women have disappeared in all, though only four bodies can be found. 

Two years on there are few answers or leads in the case. While the families of the victims are confident that the cases are linked, police aren't as certain. Still, they haven't ruled anything out, including the possibility that a serial killer is on the loose. Authorities assembled a task force, which includes members of the FBI, the county sheriff's department and local authorities, to study the series of tragedies. Suspected serial killer Neal Falls, who was killed by an escort he attacked in 2015, may be linked to the crimes, while police believe a convicted torturer named Ernest "Dollar Bill" Moore may have information about the missing six women. But for now, there are no answers for the families of the victims, or the terrified town. 

Noted town wallflower Vickie Jackson may have killed as many as 20 people between December 2000 and February 2001 – and attempted five more – but her name never earned the household recognition outside her small town. The North Texas hospital where Jackson worked as a nurse was plagued by a rash of respiratory deaths, but because the patients were all elderly, the deaths were not considered suspicious – until administrators realized several vials of mivacurium chloride, a powerful drug used to temporarily paralyze a patient's ability to breathe, had gone missing. Investigators eventually focused on Jackson after the hospital administration realized that she'd been the last one in the dead patients' rooms – and that she'd begun saying she'd "take care" of unruly hospital guests. Just over two months after her killing spree began, a syringe with traces of the drug was found in her garbage – but it took over a year, until July 2002, for Jackson to be arrested. In 2006, she pleaded no contest to charges that she took the lives of 10 people, but never admitted her guilt. She is now serving a life sentence, and as of last year was seeking a new trial.