When something as horrific as the mass murder of children in Connecticut happens, we look at Adam Lanza and his family, and we demand to know why this happened. What led to that day? Why didn’t anyone step in? What could have been done differently? I know the answer: nothing. And everything. And it doesn’t matter because it’s too late to stop what’s already happened. I know all this because my own brother is a murderer, too.

My brother and I were actually step-siblings, but when my mother met his father they moved into my house two weeks later.

I was 12, he was 16 and already well on his way to a life of trouble — he had already been enrolled in our school district’s alternative school, or “BD”, for behavioral disorders, for the last two years. My stepbrother, rumored to suffer from Fetal Alcohol Syndrome, was in and out of jail for petty crimes. Meanwhile my mother and stepfather stayed out every night until three or four in the morning and would come home drunk, stumbling and crashing into walls.

My stepfather would take the one telephone in the house with him when he went out, so that we couldn’t call friends or boyfriends. One time I stood at the top of the stairs to the basement, willing myself to slowly tip and tumble, hoping to break a leg. I wanted to prove to them why having a phone in the house would be necessary in an emergency. I couldn’t do it.

All of this led to the first time I was hospitalized for mental illness; I was thirteen. My brother had already done his time in the same psych ward for “oppositional defiant disorder” and drug abuse. I was there for what my parents assumed was drug use. It was only once someone started asking me how I actually felt that they found out I had a detailed plan for suicide and was days away from attempting it.

Despite the drugs and the mood swings, my brother was the smartest person I knew, and the only person in my family I could talk to. After long days in the outpatient program for adolescent psychiatric patients, I would come home and listen from my room to Tool and Live and the other cool bands that wafted from his room.

I would tentatively perch on the corner of the couch in the basement my brothers lived in together, which must have to them seemed like a ghetto after being forced to move into my mother’s house by their father. I didn’t mind hanging around these older boys – it was nice not being judged or analyzed or having yet another interminable joint therapy session with parents who couldn’t figure out who was to blame for my fantastically broken brain. My stepbrother told me once I was a cool girl, which was the nicest thing anyone had said to me in about a year.

When we were teenagers, our house was suffused with violence. I watched one night as my stepfather slammed his head into a wall, leaving a skull-shaped dent in the drywall that would be there until the house was repossessed. Another night, my brother sat in the basement, high and oblivious, doing nothing when I threatened my stepfather with a knife after his particularly furious and frightening bout of binge-drinking had culminated in a shoving match with my mother.

As I got older, my stepbrother grew further and further apart– mostly because my mental illness was being treated. I went to college, he didn’t.  I moved halfway across the country; he stayed in the suburb we grew up in, with the same friends and the same crushing life he’d always had.

In the decade that followed, he wavered back and forth between success and despair– most of his serious girlfriends would eventually break up with him, citing the drugs and his unhealthy relationship with his mother, who was also a drug addict. He tried to kill himself by shooting up Drano after one such breakup. On the other hand, he’d been able to continue working at the same white-collar office job for several years. He lived a life, as they say, of quiet desperation– getting by, numbing whatever pain was in his head with cocaine and pot. He was able to get out of bed and go to work but little else.

I hadn’t seen him in two years when I got the call that he murdered his wife.

The facts of the case are these: After a fight about his drug use and mental illness, he stabbed his wife 17 times. He hid her body in a closet and invited my other brother over to do coke and watch sports. Seventy two hours after killing her, he called my stepfather and admitted he had murdered someone. It’s all well-documented in police records and court transcripts.

There are so many things a crime like this brings up. It’s impossible to address them all, and one runs the risk of sounding insensitive, or forgetting about the victims, or trying too hard to humanize the person who takes a life.

But this is about the person who did it – my own personal Adam Lanza. And I make no apologies for wishing that both lives could have been saved.

The person I know, the murderer I loved, lived the same life I did. After terrifying nights of screaming, crying, begging, books and plates and glasses hurled across the room, I wrote poetry, curled up in a corner of my room, sobbing and sneaking cigarettes. He wrote stories and painted, snorting lines as he went. I got A’s and retreated into books. He retreated further into cocaine and marijuana and nihilism.

We never talked about what was happening in our house, or in our heads, but it was impossible to get any perspective when we were in the thick of it. We were struggling so much: to stay calm, to keep moving on, to act normal. One night, drinking Heineken when the house was quiet, he said to me, “I have saved your ass so many times. You have no idea how many fights I’ve kept you out of.” He meant at school, at home, everywhere. He stood up for me when no one would; we were two brilliant, fucked-up misfits in a home that could not be more dysfunctional.

When someone you know and love does something so horrible you can barely comprehend it, you don’t know how to react. When every bone in your body says it could have been prevented, people tell you you’re trying to excuse a murder. When you wake up in the middle of a dream about knives and throats and bodies piled up in your childhood home, you wonder why you haven’t committed a crime yet. You wonder what the difference is between you and him.

While my family was blended, my biological father’s health insurance was the difference between him and I. I had a therapist, a psychologist, and seven years of mental health care to set a precedent for what I was expected to do to care for myself. He was labeled the bad kid, the one with a mother who’d smoke crack with him, bottomless anger, and an illness he refused to even acknowledge.

When you’re the family member of a murderer, you become an exhibit, an “I know someone who,” a pariah. People said they always knew about our family. They said now they’d always known it was a matter of time before one of us snapped. My brother and his lawyer used his background and his medical history to try to justify his crime, and people scoffed. People said there was no excuse. When I told my boyfriend, the night I found out, he laughed and said he always knew one of us would kill someone. I had people I knew from high school come up to me at Starbucks, in the street, at bars, just to ask macabre questions about my brother and why he did it.

Why he did it. As if I knew the answer. As if I didn’t ask myself that every single day and wonder what anyone could have done. As if I didn’t wonder if the only difference between him and I was a pill a day, 50 minutes in a therapist’s office, three weeks in a psychiatric ward.

My family refused to ever discuss it. They refused to accept that anything they’d done, or hadn’t done, could have led to the murder. It became the elephant skeleton in a closet bursting with a history of things no one wanted to accept blame for. The victim’s family refused to talk to us. In their eyes, the blame was laid squarely at our feet.

And that is what we don’t talk about especially: how the blame is distributed. You can blame anyone, or no one, and yet my stepbrother’s wife is still dead. Someone is dead, someone will never get out of prison, and the rest of us will never stop thinking about blame. And I know the Lanzas will never stop either.

The last time I talked to my brother was on Christmas Day, four months before he killed the woman he married. His last words to me were about her: he said, “You’d love her. She’s a lot like you.”