SALT LAKE CITY — Mackenzie Lueck was killed by blunt force trauma to her head, being hit with such force that she died from internal bleeding, according to charging documents.

On Wednesday, disturbing new details about the violent death the 23-year-old University of Utah student suffered were revealed in court documents that formally charge Ayoola Adisa Ajayi with aggravated murder, a capital offense.

Ajayi, 31, of Salt Lake City, was also charged with aggravated kidnapping, a first-degree felony, desecration of a human body, a second-degree felony, and obstruction of justice, a third-degree felony.

Mackenzie Lueck | Associated Press

After she was killed, prosecutors say Ajayi poured gasoline on her body and burned it. Her charred remains were found by police in a shallow grave under a grove of trees in Logan Canyon on July 3.

"Mackenzie's arms were bound behind her back by a zip tie and rope. A 5-centimeter hole was located on the left side of her skull with part of her left scalp missing," according to charging documents filed in 3rd District Court.

An autopsy conducted by the Utah State Medical Examiner's Office determined Lueck died from blunt force trauma to the left side of her skull, "resulting in significant intracranial hemorrhaging which would have been fatal," the charges state.

Salt Lake County District Attorney Sim Gill declined to say Wednesday if or what kind of weapon Ajayi might have used to cause a 5-centimeter hole.

In announcing the charges, the district attorney said he had a "good and difficult" discussion on the phone with Lueck's parents prior to Wednesday's press conference. Gill paused and became emotional as he relayed a message from Lueck's parents to the community, thanking them for their support over the past three weeks.

Salt Lake County District Attorney Sim Gill announces Ayoola Ajayi, 31, of Salt Lake City, has been charged with aggravated murder and aggravated kidnapping, both first-degree felonies, desecration of a human body, a second-degree felony, and obstruction
Salt Lake County District Attorney Sim Gill announces Ayoola Ajayi, 31, of Salt Lake City, has been charged with aggravated murder and aggravated kidnapping, both first-degree felonies, desecration of a human body, a second-degree felony, and obstruction of justice, a third-degree felony, in the death University of Utah student Mackenzie Lueck, during a press conference at the Salt Lake County District Attorney offices in Salt Lake City on Wednesday, July 10, 2019. | Steve Griffin, Deseret News

"The generosity of so many strangers and friends, the support and the prayers that have helped them through this very difficult time. They are genuinely appreciative and moved by the outpouring of love and compassion," he said.

While some questions about what happened to Lueck were answered Wednesday, there are still many that remained unanswered, such as how Lueck and Ajayi first met, his motive, and whether Ajayi ultimately gave police information that led them to her body in Logan Canyon, about 85 miles north of Salt Lake City.

While Gill would not directly answer the last question Wednesday, he did stress that no deals have been made with Ajayi in exchange for information.

"I can absolutely tell you that no deals have been made, whatsoever," he said.

As for the question of whether the killing was premeditated, Gill reminded journalists that a charge of aggravated murder can be filed in Utah whether there is intent, or whether the defendant acted in such a way that the intent was to kill the victim, but it is not necessarily to prove it was a premeditated action.

Gill also stressed that the case is still ongoing and active.

"It has not come to a conclusion," he said.

In fact, Salt Lake police were back at Ajayi's house late Wednesday afternoon armed with a new search warrant looking for more evidence. Police did not say what they were looking for.

Lueck began texting Ajayi on the evening of June 16, before she flew into Salt Lake City after attending a family member’s funeral in California, Salt Lake police say. She also exchanged texts with Ajayi on the morning of June 17 after landing, the charges state. Her last text to him was at 2:58 a.m., one minute before her Lyft dropped her off at Hatch Park in North Salt Lake, according to investigators.

Gill declined to reveal the content of those text messages or why the two were meeting at a park at 3 a.m.

Lueck's cellphone was powered off at 2:59 a.m. and never came back on, the charges state. Forensic evidence collected by police placed Ajayi's cellphone back at his Salt Lake residence, 547 N. 1000 West, at 3:07 a.m., according to charging documents. That's about the time it would take to drive directly to his house in the Fairpark neighborhood from the south Davis County park.

Police formally became involved on June 20 when Lueck was reported missing.

On June 26, a large number of police officers served a search warrant on Ajayi’s home, collecting multiple bags of evidence. They were also seen digging holes in his backyard near the area where neighbors had previously seen him pouring gasoline on items and burning them.

Police found a human bone, charred muscular tissue, part of a scalp with hair, a cellphone and other charred personal items in the excavation area in Ajayi's yard, according to charging documents. More charred items were found in an alley next to Ajayi's home.

While serving the warrant, a neighbor reported noticing a "horrible smell" that was coming from the fire Ajayi set in his backyard on June 17 and 18, the charges state. Police say further investigation revealed that Ajayi had purchased a gas can at a nearby store at 9 a.m. on June 17, just six hours after picking up Lueck. That gas can was found in the trunk of Ajayi's car, according to police.

The day after officers served a search warrant on his home, Salt Lake Police Chief Mike Brown announced that Ajayi was a person of interest in the case, but no arrests had been made.

Investigators put DNA evidence they had collected on the fast track to be tested, and on the morning of June 28, a SWAT team surrounded an apartment complex at 1028 S. West Temple and took Ajayi into custody at gunpoint.

As police continued to analyze Ajayi's cellphone data, they learned he was in Logan Canyon on June 25 between 2:30 p.m. and 4:30 p.m., charging documents state. Investigators found Lueck's remains on July 3.

An initial appearance in court is scheduled for Monday, and a scheduling conference for the high-profile case has already been scheduled for July 29. Ajayi is being held without bail.

With a charge of aggravated murder, Ajayi could potentially face a possible death penalty if convicted. Gill said it was too early to say whether his office would seek the death penalty, and by law that decision doesn't have to be made until after a preliminary hearing and an arraignment.

Outside of a few traffic tickets, Ajayi has no criminal history in Utah. He at one time lived in an apartment across the street from Hatch Park, where Lueck was last seen. Ajayi and his two roommates were evicted from the North Salt Lake apartment in 2016 for failing to pay rent, according to court records.

Ajayi sporadically attended Utah State University in Logan, taking classes at times during 2009, 2010, 2015 and 2016, when he left after the fall semester, according to university officials. He never had a declared major or earned a degree.

After Ajayi was arrested, the North Park Police Department issued a statement that he had lived in North Logan from 2013 to 2015. In 2014, officers investigated a rape allegation against Ajayi, but the woman "did not wish to pursue charges in this matter" and no criminal charges were filed, according to the statement.