On July 12, 2014, Conrad Henry Roy III, 18, killed himself in his pickup truck -- nearly three years later, his friend Michelle Carter, now 20, was found guilty in a case that revolved around numerous text messages in which she encouraged Conrad to take his own life.

WATCH: Death by Text

In February 2012, Conrad Roy met Michelle Carter while both were visiting their relatives in Florida. They both lived in Massachusetts and the relationship continued. They rarely saw each other in person, but communicated almost exclusively over the phone. 

Born on Sept, 12, 1995, Conrad was the only son of Lynn Roy. Lynn describes him as "a beautiful soul" and a very happy child who grew anxious when he became a teenager.

After Conrad Roy's suicide, Michelle Carter was named "class clown" and "most likely to brighten your day" in her high school yearbook.  

As teens, both had been hospitalized: Michelle Carter for an eating disorder and Conrad Roy for a failed suicide attempt involving acetaminophen.  Many of their texts showed that they often discussed their personal issues.

In June 2014, Conrad Roy graduated from high school with a 3.88 GPA and simultaneously earned his captain's license from Northeast Maritime Institute.

On June 13, 2014, Conrad Roy recorded a video of himself on his computer. In the video, he discussed his battle with depression, suicidal thoughts, and social anxiety.  At one point, he said, "I need to be comfortable in my skin.  And in order to be comfortable in my skin, I have to just be happy and live with myself for who I am: Conrad Roy III." 

A month after recording that video, Conrad Roy's body was found in his pickup truck in a Kmart parking lot in Fairhaven, Mass.

Teen suicide: Risk factors, warning signs and prevention

Using a gasoline powered water pump that he placed in his pickup truck, Conrad Roy died after purposely inhaling deadly carbon monoxide.

In an interview with "48 Hours," Conrad's sister, Camdyn, left, tells correspondent Erin Moriarty that on the night of Conrad's death, she received a text from Michelle Carter: 

"Hey Camdyn it's Michelle Carter! Idk if you remember me, but I'm dating your brother again haha and he hasn't answered me and I'm just starting to get a little worried. Is he okay?"

In the days following Conrad Roy's suicide, Fairhaven Police Detective Scott R.Gordon began looking through Conrad's phone. Detective Gordon testified that when he unlocked it, there was only one thread of text conversation on the phone.  It was with Michelle Carter. 

In March 2015, Michelle's parents, Gail and David Carter, released this statement to the Boston Herald: 

"Our hearts have and remain broken for the Roy family. For everyone that does not know our daughter, she is not the villain the media is portraying her to be. She is a quiet, kind, and sympathetic young girl. She tried immensely to help Mr. Roy in his battle with depression. We know that once all of the facts are released, our daughter will be found innocent."

After recovering all the text messages shared between Conrad Roy and Michelle Carter, Det. Gordon uncovered thousands of texts, many encouraging Conrad to kill himself. Many of those texts were shown as evidence during her trial.

WATCH: Michelle Carter and Conrad Roy's texts

On July 4, 2014, a week before Conrad Roy's death, Michelle Carter sent him a series of angry texts after a failed suicide attempt the previous night:

Conrad Roy: hey sorry I just took sleeping pills and fell asleep

Michelle Carter: So it didn't work

Michelle Carter: That's such a lie

Michelle Carter: You said you wanted this bad. I knew you weren't gonna try hard

Michelle Carter: I feel like such an idiot

Conrad Roy: Why

Michelle Carter: Because you didn't even do anything! You lied about this whole thing! You said you were gonna go to the woods and do it and you said things that made me feel like maybe you were actually serious, and I poured my heart out to you thinking this was gonna be the last time I talked to you. And then you tell me you took sleeping pills? Whixh [sic] first of all I know that's a lie because you already said you wouldn't get enough and idk how you would of [sic] got them. I'm just so confused. I thought you really wanted to die but apparently you don't, I feel played and just stupid

Conrad Roy: Don't I found out a new plan. and I'm gonna fo [sic] it tonight

Michelle Carter: I don't believe you

Michelle Carter: You're gonna have to prove me wrong because I just don't think you really want this. You just keeps [sic] pushing it off to another night and say you'll do it but you never do

Conrad Roy: okay

Michelle Carter: Okay what?

Conrad Roy: I'll prove you wrong

Michelle Carter: What are you planning on doing?

Michelle Carter: Poision [sic] would work

Conrad Roy: Carbon monoxide or helium gas. I want to deprive myself of oxygen

Conrad Roy: don't feel like an idiot it's gonna happen

Michelle Carter: Tonight?

Conrad Roy: Eventually

Michelle Carter: Cute J haha I love you

Michelle Carter: SEE THATS WHAT I MEAN. YOU KEEP PUSHING IT OFF! You just said you were gonna do it tonight and now you're saying eventually….

Early in the morning on July 12, 2014, Michelle Carter and Conrad Roy exchanged a series of texts about him killing himself.  Conrad took his life in his truck later that day.

Michelle Carter: "So I guess you aren't gonna do it then, all that for nothing"

Michelle Carter: "I'm just confused like you were so ready and determined"

Conrad Roy: "I am gonna eventfully [sic]"

Conrad Roy: "I really don't know what I'm waiting for. . . but I have everything lined up"

Michelle Carter: "No you're not, Conrad. Last night was it. You keep pushing it off and you say you'll do it but u never do. Its always gonna be that way if u don't take action"

Michelle Carter: "You're just making it harder on yourself by pushing it off, you just have to do it"

Michelle Carter: "Do u wanna do it now?"

Conrad Roy: "Is it too late?"

Conrad Roy: "Idkk [sic] it's already light outside"

Conrad Roy: "I'm gonna go back to sleep, love you I'll text you tomorrow"

Michelle Carter: "No? Its probably the best time now because everyone's sleeping. Just go somewhere in your truck. And no one's really out right now because it's an awkward time"

Michelle Carter: "If u don't do it now you're never gonna do it"

Michelle Carter: "And u can say you'll do it tomorrow but you probably won't"

During the trial, Michelle Carter''s friend, Samantha Boardman, read a text that she had received from Michelle in September 2014 that said:

 "…I could have stopped him I was on the phone with him and he got out of the car because it was working and he got scared and I f---ing told him to get back in..."

Assistant District Attorney Katie Rayburn contended that Michelle Carter was "virtually present" when Conrad Roy killed himself.  "She was in his ear," said Rayburn. "She was in his mind.  She was on the phone.  And she was telling him to get back in the car, even though she knew he was going to die.  And she did it for attention."

Michelle Carter's defense attorney, Joseph Cataldo, argued that Conrad Roy "dragged Michelle into this."  According to Cataldo, Conrad wanted and intended to kill himself. He alone is responsible for his death and that the text messages prove it.  

As a witness for the defense, Dr. Peter Breggin, a psychiatrist and critic of the use of prescription drugs in psychiatry, testified that Michelle Carter, who was on antidepressants at the time of Conrad Roy's death, was "involuntarily intoxicated," which caused her to go through a transformation and want to help Conrad kill himself. Dr. Breggin also argued that Conrad took advantage of Michelle and coerced her into helping him with his plan to die. 

Camdyn Roy tells Erin Moriarty that even though Michelle Carter wasn't in the car with Conrad physically, she was there.  "She could've stopped him," said Camdyn. "She could've even been like, 'Conrad, don't do this.' But she didn't." 

Conrad's youngest sister, Morgan, said that even though Conrad was depressed, Michelle "just made it worse."

In her first TV interview, Lynn Roy tells "48 Hours"' Erin Moriarty that Michelle Carter "should be held accountable for her actions," "needs rehabilitation," and that "she knew exactly what she was doing and what she said."  

Having opted for a bench trial, Michelle Carter chose to have her fate decided by one man, Juvenile Court Judge Lawrence Moniz, rather than a jury.  As such, Judge Moniz served as fact-finder in the trial.

Lynn Roy tells "48 Hours" that it doesn't matter what happens in the courtroom. "It's not gonna bring him back," she said.  "I just hope that it makes a difference—some kind of precedence." Lynn hopes that Conrad's story will bring about a new law.

On June 16, 2017, Judge Moniz ruled Michelle Carter guilty of involuntary manslaughter in the death of Conrad Roy.

WATCH: Death by Text: The case against Michelle Carter 

On Aug. 3, 2017, Judge Moniz sentenced Michelle Carter to two-and-a-half years in jail, but ruled she would be eligible for probation after 15 months.WATCH: Death by Text