(CNN) Exactly a year ago today, Avijit Roy was hacked to death in the most public of places : Coming out of a crowded book fair in Dhaka, Bangladesh. His crime? He was an American blogger who wrote prominently about secular issues -- works that his misguided attackers viewed as blasphemous. In the months that followed, fundamentalists carried out several other attacks on secular writers.

In the piece below, Roy's stepdaughter Trisha Ahmed, a second-year student at Johns Hopkins University, recounts the father she remembers and the attack she's trying to forget.

2008

For a while, it felt strange to call him "Dad" because he had the aura and wit of a fun uncle. When we moved into a new house in the summer after my sixth grade, he picked up two long sticks in the backyard, and passed one to me.

"Sword fight?" he challenged.

"It'll be my pleasure to beat you," I snarked back.

We waved our wooden swords at each other until it got dark outside. Every time I lost, I wanted a rematch. And I lost every time.

I asked him one day why he never let me win.

"Don't you want me to treat you as my equal?" he asked.

Avijit Roy pictured with step-daughter Trisha Ahmed and wife Rafida Ahmed Banya.

2012

Though my dad worked as a computer programmer during the day, he was a writer when he came home. His books were about the science behind homosexuality and the "virus" of religious extremism. With the goal of incorporating more secular discussion into mainstream Bangladesh, he was also becoming a well-known activist.

One month before the national AP exam during my 11th grade, my calculus teacher quit. He told us he was sorry to leave, but that he had to because he wasn't making enough money as a high school teacher.

My dad and I struck a deal. He would help me with calculus and physics, if I would help him transition into writing in English.

"Dad, these sentences are horrible. How have you been getting by with this kind of grammar?"

"Trisha, please just make the edits. The content is good."

And it always was. We had a good thing going.

February 13, 2015

Every February, a national book fair is held in Dhaka, my parents' hometown in Bangladesh. Before flying there, my parents decided to visit me at Johns Hopkins University in Baltimore, where I was now a student.

They brought me a box full of presents: Candy, clothes, notebooks, pens. I felt guilty for not getting them anything, so I quickly pulled two scarves out of my backpack.

JUST WATCHED U.S. Blogger Hacked To Death In Bangladesh Replay More Videos ... MUST WATCH U.S. Blogger Hacked To Death In Bangladesh 06:00

My dad wore the scarf all night long.

"You give him a new thing, and he'll wear the hell out of it with pride," my mom joked.

February 26 (morning)

At 10:30 a.m., I took a seat in the back of my 300-person lecture class in cognitive neuroscience. At noon, I checked my phone and saw three unread messages from my cousins in Bangladesh.

Tears streamed down my face. My body shook. I dialed my roommate.

"What's wrong?" she asked. "Are you okay?"

"My dad's dead and my mom's in the ICU in Bangladesh."

February 26 (afternoon)

With swollen, dead eyes, ringed in red, I posted on Facebook:

My dad was a prominent Bengali writer, most famous for his books about science and atheism. He and my mom went to Bangladesh last week to publicize his books at Bangladesh's national book fair. 15 hours ago, Islamic fundamentalists stabbed my dad to death. My mom was severely wounded from the attack and is still in the hospital. His death is headline news in Bangladesh.

The reason I'm sharing this is less for me and more for my dad. He was a firm believer in voicing your opinion to better the world.

He and my mom started dating when I was six years old. In the twelve years that followed, he became my friend, my hero, my most trusted confidante, my dance partner (even though we're both terrible dancers), and my father. Not once did he tell me to simmer down or be more polite; he taught me to be informed, bold, and unafraid.

To say that I'm furious or heartbroken would be an understatement. But as [screwed] up as the world is, there's never a reason to stop fighting to make it better. I'll carry the lessons he taught me and the love he gave me forever. I love you so much, Dad. Thank you for every single thing <3

#‎WordsCannotBeKilled

Those are the words the public saw.

But what they didn't see was me downing sleep medicine every night, so I wouldn't dream of my dad lying in a pool of his own blood. What they didn't see was the worry that I wouldn't see my mom again, and that if I did, she would never be the same, and I would be an incompetent caretaker. What they didn't see was me watching Bangladeshi news networks at all hours of the day, watching footage of thousands of people marching in the streets with my dad's face painted on banners, demanding justice for his murder.

What they didn't see was a girl who had gone mute.

March 3

I didn't recognize my mom at first when she returned to the States. Her head was shaved. I thought of when she was diagnosed with thyroid cancer -- how shrunken and slow she became during treatment, how my chest felt intensely hollow for days at a time.

It was 10 p.m., and I stood in the airport to greet her. She was surrounded by a doctor, an FBI agent and a handful of security guards. We watched incredulously as she cracked a joke with the man who pushed her wheelchair.

Roy's death sparked a wave of mourning and widespread condemnation of the attack in Bangladesh.

My grandfather sobbed at the sight of her. He stroked his fingers over her shaven head, over and over, around the bandages.

The doctors at the Mayo Clinic, where she was taken, unraveled her bandages, and my eyes fell on her stitches. She'd been stabbed four times around the head, but none of them resulted in direct brain damage. Her thumb had been sliced off from the attack. Black spots dotted my vision, and I stumbled into a chair, which became my home for the night.

She started to weep when she thought I was asleep. I slowly ran my fingers down her arms, down her back, until she was calm. It's an old trick my grandma's mom taught her, who taught my mom, who taught me.

March 22

I flew back to campus alone. I was told that the same group that killed my dad could still be targeting my mom and me. My mom instructed me not to go anywhere alone, no matter the time of day, and not to go anywhere at night, period. I met with an FBI representative. She assured me I was most likely safe. But that didn't stop the paranoia from seeping in.

May 3

JUST WATCHED Killed for his views Replay More Videos ... MUST WATCH Killed for his views 01:57

The leader of Al Qaeda's branch in the Indian subcontinent published a video that claimed responsibility for murdering Avijit Roy in the name of Islam.

May 26

I was home in Georgia after a long and tired semester. It felt eerie. With every corner I turned, I expected to see my dad typing in his study or reading in my parents' bedroom.

It had been three months since the attack. I was on the floor, crying. Nothing seemed real. I got on the balcony, and readied myself to jump. My boyfriend found me before I did. He helped me back inside and put me to bed.

September

While my dad spent most of his life reading about science and secularism, my mom spent most of hers reading about politics and history and feminism and cultures of the world. After a few months at work, my mom decided to take a leave from her job as a senior director at a credit bureau.

"Are you sure this is what you want to do?" I asked her.

Father and daughter during one of their lighter moments.

"Who knows?" she laughed. "I was thinking today that your dad died for his passion, so I should at least try living for mine."

Within a week, she was out of the country, meeting with humanist associations all over Europe. She began working to get other activists out of Bangladesh, before they could suffer the same fate as my dad. Although my mom hadn't sorted through all of her own issues yet, she wanted desperately to help others get to safety.

Today

As brutal as his death was, I don't think my dad would have wanted to live any differently. By dying for his cause, he gained worldwide attention to the oppression and murder of scientific thought in Bangladesh -- a country that claims to be governed by secular principles.

I know that Al Qaeda, ISIS, and other manifestations of religious extremism are alive and well. But by writing and sharing my story, I am making my impact. I -- and so many others -- am slowly, thoughtfully, and certainly chipping away at the ideologies that seek to destroy us.