A jealous teen sedated his friend with a concoction of drugs in a Gatorade bottle, then used a belt to strangle him, prosecutors alleged in a Florida courtroom.
Pedro Bravo, 20, is accused of killing Christian Aguilar in 2012. Authorities say he was enraged after discovering that Aguilar was dating his ex-girlfriend Erika Friman. The three were high school friends.
Prosecutors revealed new evidence in the case Thursday, including a photograph of the belt they say Bravo used to kill Aguilar.
The slaying took place inside Bravo's SUV in a Gainesville, Florida, Walmart parking lot, authorities allege.
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Prosecutors revealed photos of a cracked windshield covered in duct tape and blood stains on the SUV's seats, along with a blood-stained paint can and shoes - signs of a violent struggle, authorities said. Another image showed a mud-caked shovel found behind Bravo's Gainesville apartment, which prosecutors say was possibly used by Bravo to bury his victim.
Surveillance footage shows Bravo buying a shovel, duct tape, bandages and over-the-counter sleep aids the night before Aguilar went missing.
Prosecutors claim that Aguilar's death was the result of his relationship with Friman. Friman dated Bravo in high school, but after Friman entered college, she began dating Aguilar. She testified Wednesday, saying she hid the relationship from Bravo.
"I lied to him because he was at a very sensitive point in his life, I supposed," she said in court Wednesday. "I didn't want to throw him over the edge and say, 'By the way, I'm dating a mutual friend of ours.'"
Aguilar's body was found in a remote field, police said, discovered 22 days after he went missing.
Bravo's sketch pad has been a main focus. Authorities say he filled the pad with hate-fueled messages.
"No one will stop me," he wrote in one passage, prosecutors say. "I will get out of Miami and into Gainesville by January 2013 and I will get her back."
Friman told the court Wednesday that she arranged for Bravo and Aguilar to meet after Bravo threatened suicide, hoping the advice from Aguilar would help.
Bravo has denied killing Aguilar.
ABC News Chief Legal Affairs Anchor Dan Abrams said the case against Bravo is incredibly strong because of the amount of evidence.
"They've got surveillance pictures, the defendant's journal, blood evidence, computer searches. They have just about every kind of evidence possible," Abrams said.
"And the defendant admits he had a fight with the victim on the day he disappeared and punched him repeatedly, but contends he was alive when he left him."
Accused Teen Killer Strangled Friend With Belt: Prosecutors