TROOPER: My name is Grant Hendrix. I'm a trooper with the Missouri State Highway Patrol. I'm at the site of Mariah West's accident. Mariah's vehicle traveled across this median and ended in – striking the bridge that you can see behind me.

When I got to the scene...her face was disfigured from sliding down the roadway. It's funny, the first thing I noticed about her was her shoes. (Chuckles) Lying in the roadway in a large pool of blood, I noticed her shoes and I thought, "This is a young girl."

That's the first thing I thought when I saw this. And at that point is when I noticed her cap and gown was still in her car.

She was going to graduate the next day. It was just a really horrific scene all because of a senseless text message. It's just sad. Sorry. It's just sad.

SISTER: Ashley would text hundreds of messages every day. That was the way we kept in touch. We would definitely text more than we talked.

MOTHER: Mariah was a multi-tasker extraordinaire.

FRIEND #1: She could text better than anyone I know. She could be having one conversation with me, completely focused...while having a text conversation with somebody else.

GUY: When you do something 7,000 times a month, you tend to learn where those 26 letters are. We would be at school, at home, movies, bowling, driving. Not even looking at her phone. Just simple, insignificant, useless (bleep) whatever it may be, about anything and everything. Just a way to pass time. It didn't matter where we were. We were constantly texting.

SISTER: This is my sister. She was looking at my message that I had just sent her. When she looked up, she had clipped the median on the left hand side of the road. Her truck flipped and as it was flipping, she was actually ejected through the driver's side door and she landed in the ditch about 300 feet from her truck.

People will tell you over and over again, it's not your fault, but knowing that you were the person she was talking to when she was killed...just having a highway patrol officer write in a report that a text message sent at 12:05 is the reason that she is dead is not something that will ever go away.

If I could talk to her one last time, I would just say I'm sorry. This is her cell phone that she used in the accident. Four little letters. That's what killed her.

GUY: You never really think about it, but people associate drinking and driving as a dangerous thing. Your vision's impaired, your judgement's impaired, but if you look at texting and driving, your vision's not even there. You're not even looking at the road. (Crashing sound)

If someone were to ask me to drive down the road and close your eyes for five seconds or six seconds, I would never even attempt that, but then if someone asks, "Read this text message and respond to that in about the same length of time," well, that would be no problem. I've done that numerous times in the past before this accident.

I was on my way home, I had my girlfriend in the car, and I'm just reading a text message, responding. I was looking up every couple seconds or so like I always did, and I just hear a loud scream next to me, and the next second I look up and I see a bicyclist crash in the windshield.

When I got out of the car, he didn't have a pulse, he wasn't breathing, he wasn't alive. There are no words to describe the level of grief, the level of depression and self-hatred I was going through.

My first year of college, I just remember one girl recognizing me and saying, "Oh, I remember hearing about you. You're that guy who hit the bicyclist 'cause you were texting and driving." That was actually the day before I ended up going to the hospital for emotional problems.

I sent one stupid meaningless text, "LOL," and killed a man.

MALE VICTIM: People don't realize it could just take three seconds.

I was going to the movies and their car just went directly in the tree and it was a direct collision. I was the passenger, I collided with a tree on my right temple, and I was declared dead on the scene three times.

I used to be able to drive. I used to be able to go for walks. I used to be able to run around town by myself. I used to have a job. I was normal, and all this I cannot do anymore because they had to text.

This is the text message that changed my life forever.

MOTHER: The day before her graduation, my daughter drove to go meet a boy, and she never made it. Today she would have been 19 years old exactly.

FRIEND #2: Mariah never wanted a minute to go by that she wasn't doing something. She wanted to do everything all at one time with friends and family and just having a good time. That's what she loved. Friends would tell me from school that, you know, the best part of the day at school was Mariah coming down the hall because she'd stop to give everyone a hug.

(Indistinct conversations)

OK guys, in honor of Mariah. (Singing) Happy birthday to you, happy birthday to you, happy birthday dear Mariah.

FRIEND #2: She had met a guy who played baseball, and one evening, she just spontaneously got in a car, and said, "Hey, I'm going to come watch his game." He was texting her to tell her directions of where she needed to go.

FRIEND #1: And I guess she just looked away for too long. Where you at? You know? Like that was it.

MOTHER: One of her friends had no idea that she had been in an accident, so he kept texting. We ended up having to send him a text back to say, "Please, stop. She's in critical condition in the hospital and we don't know if she'll even make it."

FRIEND #3: She always worked her magic, you know, and still to this day, without her being here, she's so much still a part of our lives every day. She was our sunshine. She really was. (Sniffling) She was.

MOTHER: It's a simple text message. "Where you at." Three simple words.

TROOPER: She paid the ultimate price for her actions. I've had to do this more than once. Mariah's not the only – The only victim that I've dealt with. It never gets any easier, and it won't get any easier. What is worth losing your life over? That text message?