The man accused of killing University of Utah student Mackenzie Lueck has been charged with murder days after police found her body in a shallow grave, the Salt Lake County District Attorney’s Office said on Wednesday.

Ayoola Ajayi, a 31-year-old former Army IT specialist, was formally charged Tuesday with aggravated murder, aggravated kidnapping, desecration of a human body, and obstruction of justice. On July 3, authorities found Lueck’s body in a shallow grave about an hour from the park where she was last seen.

Ajayi, who was booked into jail on June 28, may face the death penalty if convicted.

“Mackenzie’s arms were bound behind her back by a zip tie and rope,” Salt Lake County District Attorney Sim Gill said during a Wednesday press conference announcing the charges. “A five-centimeter hole was located on the left side of her skull with part of her left scalp missing.”

On June 17, the 23-year-old Lueck arrived at the Salt Lake International Airport at around 2:30 a.m. after attending a family funeral in California. According to police, Lueck then took a Lyft to Hatch Park in North Salt Lake. The Lyft driver dropped her off at around 3 a.m.

“Mackenzie was met at Hatch Park by an individual in a vehicle,” Salt Lake City Police Assistant Chief Tim Doubt previously told reporters.

Phone records show Lueck started texting with Ajayi one day prior and sent her last text to him before 3 a.m., Gill said Wednesday, declining to comment on the details of their conversation. According to a probable cause affidavit obtained by The Daily Beast, “cell phone records for both Mackenzie and Ajayi place them at Hatch Park” right after she was dropped off.

“A forensic analysis of phone records shows that Ajayi’s phone was back at this residence ...at approximately 3:07 a.m..,” the affidavit continued. The 31-year-old’s home is about a seven-minute drive from Hatch Park.

On Friday, authorities found Lueck’s “charred” body in a “wooded area, in a shallow grave with brush over it” in Logan Canyon. Her arms were bound with a zip tie and rope, and part of her left scalp was missing. Phone records indicate Ajayi was in the canyon on June 25, Gill said.

A medical examiner determined the 23-year-old suffered blunt force trauma to the skull and ruled her death a homicide, Gill said. While details of Ajayi’s motive were not immediately known, Gill told reporters on Wednesday the case “is still active and open” and the death penalty is “a possibility.”

Gill also declined to comment on Leuck and Ajayi’s “prior history.” “This case is far from over,” he said.

During an all-night search of Ajayi’s home on June 26, the affidavit states, investigators discovered “a human bone, charred muscular tissue, part of a scalp with hair, a cell phone, and other charred personal items” inside a “freshly dug site” behind the garage.

“Furthermore, in the alleyway adjacent to Ajayi’s home, investigators located charred black fabric, buckles and other items of evidentiary value,” the affidavit states, adding that the DNA matched that of Lueck’s personal items. Ajayi’s neighbors confirmed to police they had seen him using gasoline to burn something in the backyard and smelled something “horrible” a few days prior. A gasoline can was also found in the trunk of his car, the affidavit said.

According to public records, Ajayi has no criminal history in Utah other than two traffic citations. In 2012, the 31-year-old was barred from Utah State University after authorities suspected he stole an iPad from campus.

During their investigation, according to campus police records, authorities learned the Nigerian immigrant was overstaying his visa and alleged he was using the iPad to find a wife to avoid deportation. While Ajayi had stopped attending USU classes that year, he was still sleeping on residence hall couches and stashing his belongings in a janitor’s closet.

Two years later, one of Ajayi’s coworkers reported to North Park police that he allegedly sexually assaulted her, though he was never criminally charged. Ajayi’s first court appearance will be next week, Gill said.