How a College Love Triangle Ended in Death

One Florida college student wouldn't let anything get in the way of his plan to win back his ex-girlfriend, even if it meant killing his own friend.

Pedro Bravo, 20, was found guilty of first-degree murder and six other counts in the death of his friend Christian Aguilar, 18, last week.

Watch the full story on ABC News' "20/20" TONIGHT at 10 p.m. ET.

Girlfriend at Center of Gainesville Love Triangle Never Thought Killer Ex Was Capable of Murder

The Inner Thoughts of a Killer: Inside Pedro Bravo's Journal

Aguilar had been dating Bravo's ex-girlfriend, Erika Friman. Friman told ABC News' "20/20" that she hid the relationship from Bravo, because he was still upset over losing her.

"I just felt like he needed more time before hearing it," said Friman.

But when he did find out about Friman and Aguilar's relationship in September 2012, prosecutors claimed Bravo carried out a plan to kill Aguilar.

"I don't think anyone in their right mind would go as far as he has," Friman said.

Click through to see how Bravo's attempt to win back his ex-girlfriend eventually ended in murder.

Pedro Bravo and Erika Friman, seen here together, started dating in their sophomore year of high school. Bravo was Friman's first boyfriend.

But by the time the two graduated high school in summer 2012, Friman ended the relationship.

"I told [my family] that it was for the best and that I just wasn't happy and that he would be fine," Friman told "20/20." "I didn't really think he'd have an issue. I thought time would heal all."

Christian Aguilar was a freshman at University of Florida and had been friends with Bravo since the eighth grade. Aguilar, Bravo and Friman were friends throughout high school.

"He was shy with people he didn't know, but once he got to know you, he would just open up," Aguilar's brother Alexander Aguilar told "20/20."

After Friman had broken up with Bravo, Friman said she and Aguilar both realized they liked each other as more than just friends.

"Christian made me really happy, and we had so many things in common," said Friman.

Aguilar and Friman, who was attending Sante Fe Community College in Gainesville, Florida, eventually began dating after she broke up with Bravo.

"I was so happy," Friman said of the relationship. "I think we were soul mates."

Friman and Aguilar are shown together in this photo. Friman told "20/20" she hid their relationship from Bravo.

"I lied to him, I told him, 'No we're not dating ... We're just hanging out,'" Friman recalled. "I had already known that he was suicidal, and I didn't want to throw him over the edge."

Bravo was crushed to find out Aguilar and Friman were dating.

He detailed his feelings about his breakup with Friman and his ideas and plans for winning her back among other entries in his journal, pictured here, which came into focus during his murder trial.

The Inner Thoughts of a Killer: Inside Pedro Bravo's Journal

"How do I feel? I feel as if someone stabbed me in the chest and was sorry all throughout as they just pressed deeper," Bravo wrote in his journal on Aug. 13, 2012. "Go on and win her back."

In September 2012, Friman said Bravo reached out to Aguilar, saying that he was struggling with his depression and needed help.

Aguilar and Bravo met up and drove around Gainesville in Bravo's SUV, seen here. They were shown on surveillance camera footage shopping together.

On Sept. 21, 2012, Aguilar was reported missing. Two days later, police identified Bravo as a person of interest in his disappearance.

"We had hope of finding him," said Aguilar's brother Alexander Aguilar. "I mean, it slowly started going away when you're reaching day four and five, and there's no trace of him."

It's in Bravo's SUV in a Gainesville Walmart parking lot where authorities alleged Bravo killed Aguilar.

Before Aguilar went missing, store surveillance camera footage showed Bravo buying a shovel, duct tape, bandages and over-the-counter sleeping aids.

At Bravo's trial, prosecutors alleged that Bravo poisoned Aguilar with the sleeping aids mixed in a sports drink.

In this evidence photo, a sports drink bottle and sleeping aids are pictured among other items found in Bravo's car.

Prosecutors claim that after Bravo poisoned Aguilar, he then strangled him.

The prosecution presented this belt found in Bravo's SUV, pictured here in this evidence photo, as a theory for how Bravo killed Aguilar.

In this evidence photo, pieces of duct tape are pictured near where Aguilar's body was found in a forest in rural Levy County, Florida, about 60 miles southwest of Gainesville.

When Aguilar wouldn't answer his phone hours after he went to meet Bravo, Friman said she started to panic. Friman then said she made Bravo go with her to the police to report him missing.

Bravo was charged with first-degree murder on Sept. 28, 2012.

In police interrogation tapes played in court, Bravo told police that he met up with Aguilar on the night of his death and that the two got into an argument.

"He got out of the car and I fought him and after that, I remember going in the car and I remember seeing him in my rear view mirror while I was driving away," Bravo told police during the interrogation.

Aguilar's backpack, seen here in this evidence photo, was key evidence at Bravo's trial. The backpack was found in Bravo's apartment hidden inside of another backpack.

Aguilar's body was found 22 days after his disappearance.

On Oct. 19, 2012, Bravo pleaded not guilty to murder and kidnapping charges. He pleaded not guilty in November to five additional charges in Aguilar's death.

On Aug. 16, 2014, a jury deliberated for almost four hours before finding Bravo guilty of first-degree murder and six other counts in Aguilar's death.

Bravo was sentenced to life in prison without the possibility of parole.

Upon hearing the guilty verdict, Friman said she was relieved.

"I was happy I didn't have to worry anymore," Friman said.

Watch the full story on ABC News' "20/20" TONIGHT at 10 p.m. ET.

After Christian's death, the family launched the Christian Aguilar Search and Rescue Foundation to create a network of trained dogs ready to be dispatched to help search for missing people all across the country. For more information, visit their website, http://casark9.com/