The people in the following examples were perceived as fairly "normal," initially.

Steve Was Weird

"Well this is wild."

"I know a guy who murdered a nurse and wanted our towns first serial killer. He bought a 'murder kit' online and stabbed her over 50 times. Let's call him Steve."

"I knew him through scouts. Now, to preface, our scout troop was pretty laid back. We didn't tend to bother with badges and the two troop leaders were pretty cool guys. Mostly we played silly games like crab football, built catapults to fire stuff across the hall at each other etc. You get the picture."

"We were a little bit a gang of misfits. But Steve was really weird. First time it came out was when he would do this thing where he'd get his butt out and dance around. At first it was like outrageous and funny, and he kept getting told to stop. When he kept doing it got a bit annoying (none of us were keen to see his bare arse...), then it got boring, then just outright weird when its not remotely funny, no one wanted him to do it and he continued."

"A few times he was suspended for a week or so but give we were quite laid back and the troop leaders were good guys, they probably couldn't bring themselves to bin him off completely."

"It was a long time ago so I can't recall all the details but I recall him being quite childish in mentality but also veeeery creepy."

"When I found out i was shocked, but not surprised. Then I remembered I'd played hide and seek in the dark with this guy, in a hall with a kitchen full of knives..."

– Nome3000

He Never Seemed Violent

"Sat next to him in choir class. He was always kind of off. He operated on his own wavelength. Constantly in his own world, never really engaging with anybody. People just didn't really exist on his radar. On a class trip we slept in the same hotel room and he walked around naked like I wasn't even there. I always assumed he was autistic, but in hindsight it might have been something much worse, like schizophrenia. He never seemed violent, but nobody ever talked to him enough to ever make that conclusion in the first place."

"A few months ago he beat and stabbed his mother to death with a kitchen knife. It was so bad dental records were needed to identify the body. He cut off one of her breasts and implied in his confession that he ate part of it. He waited until his dad came home from work to show him what he'd done. Claimed he saw a sign from the devil that told him to kill her. (That may have been a lie. From what I heard he was very excited to tell the police what he had done. And from what I do know about him, he might have said it for the attention.) He turned himself in, waived his Miranda rights, and confessed to everything. When the cops found him he was literally soaked in blood. He refused to shower it off, so they had to hose him down before they put him in a cell. He's looking at 40 years in prison."

"His Mom was an amazing woman, she tailored our suits for choir and was constantly volunteering. If there was an event, she was there. She was gonna be her town's councilwoman next year. She loved her son very much. She didn't deserve to die like that."

– Alsikepike

You never really know about a person.

Everybody Loved The Guy

"One of the smartest, most popular, and friendliest guys at my high school. He stood up for people who got bullied, he included everyone, he helped people who needed it all the time. Seemed like an utterly selfless guy. Literally everybody loved the guy. Two years ago killed his wife and then himself after an argument."

– anon

He Seemed Friendly Enough

"Obligatory didn’t know him as a friend, but a regular customer in my shop. He would come in after his shift to buy beer and tobacco, on one occasion he caught and helped us to evict a shoplifter. He seemed friendly enough. Then a local girl went missing and was eventually pulled out of a river a few weeks later. They announced they were looking for somebody in connection with her death and it was him. They had CCTV footage of him tailing her through a park and footage of him buying beer in a shop, still unconfirmed to this day being our shop as they blurred out the surroundings."

"Anyway, as we had a TV in our shop switched to the news channel as it was a rolling story local to us, we started to discuss the guy, if we saw him on the day she went missing, that kind of thing. We hadn’t, but it was at that point when one of my staff, a young girl, who had previously said to management that she didn’t want to work the closing shift anymore because there was 'too many creepy men around,' told us that he used to stare at her when he came in to the store in a way that made her uncomfortable enough to not want to be on the floor when he came in."

"They never got to question him about the murder as he was found dead in a local park a few days later. He’d hung himself."

– anon

Nothing Really Stuck Out At The Time

"I worked in a food court in my early 20s. This family would come in pretty regularly. The family stuck out because they were giants. Mom was easily 6'1" and dad was 6'7". They had a few kids. Nothing really stuck out at the time. They never seemed happy but never fought. They just always looked like they were just coming out of mourning."

"I heard a few years back that the mom decided to leave the dad. The dad murdered the whole family and then killed himself."

"Another coworker did something similar. He lived with his elderly dad. He was a super nice, but just always had this deep sadness behind his face. His gf broke up with him, his dads health went south. Everything became too much so he shot his dad and then himself. Even after hearing that, i felt bad for him. He seemed like a dude with a big heart and if he just had a day to decompress and someone to talk to, i think it would have gone a lot differently."

– rand0yes0

He Seemed A Little Distant

"I went through primary and high school with a guy in the year below me who seemed a little... distant. We lived near each other and caught the bus from the same stop. He was a bit of a bully but it was something more. Like you could tell he wasn’t a bully because he was hurting inside or because he felt threatened in some way, he was a bully because he did what he wanted to do and didn’t realise that it hurt other people. Like the kind of kid who enjoyed pulling wings off flies."

"Not long after I left my hometown I heard that he had been charged with the murder of a 2 year old. Apparently his girlfriend at the time left her daughter with him for an hour or so while she ran an errand. He couldn’t deal with the toddler crying anymore so he beat her. He caused severe internal bleeding and she died in hospital not long after. He would have been around 22 when he did it. He was sentenced to 36 years with a non parole period of 27 years."

"Edit: this happened in Australia around 2014."

– Adelineslife

He Gave Away Pocket Knives

"I worked at a box store about 20 years ago, a guy I worked with was always 'off,' and would give away pocket knives to other employees. One day he came in with scratches all over his face; he murdered a disabled girl the day before, using a pocket knife he had given our co-worker later that day."

– Grover_washington_jr

The most unsettling thing is, anyone is capable of taking someone else's life.

It just takes a moment for someone to snap and periodically lose any sense of judgment and act out on their rage.

Worse, there are those who are on the prowl and have every intention of causing harm. You just never know who these people who are capable of such atrocities look like.

You think you know someone...