Florida police say four teens hacked a 17-year-old boy half to death with a machete before ordering him into a hole and burying him while still barely alive. Then two of the alleged attackers celebrated by having sex nearby.

Desiray Strickland, 18, was arrested Wednesday in the sickening murder of Jose Amaya Guardado on June 28. Kaheem Arbelo, 20, Jonathan Lucas, 18, and Christian Colon, 19, were arrested last week, and reportedly confessed to the crime.

The foursome apparently plotted the gruesome killing for a couple of weeks, according to court documents obtained by the Miami Herald. They allegedly dug a hole and hid the machete in advance. The motive is still unknown, but police believe Guardado owed one of them money.

All five attended the Homestead Job Corps campus, a government-run free education centre. According to the documents, the four allegedly lured Guardado from the school to a nearby wooded area, where they attacked him.

"The victim made one last attempt to fight off the attackers," the Herald quotes the police report, "at which time, (Arbelo) struck the victim with the machete several more times until the victim's face caved in."

Then they ordered Guardado into his shallow grave and buried him while he was still clinging to life, police say.

According to the report, Lucas and Colon headed back to the centre, but Strickland and Arbelo lingered behind to have sex.

Guardado's body was reportedly discovered three days later by his brothers, who were searching for him after he was reported missing.