(CNN) Before Aaron Hernandez hanged himself, he stuffed cardboard in the tracks of his cell door, making it difficult for prison officers to enter and render aid.

That was not a new tactic for Hernandez. He had twice previously been disciplined for tampering with the door and covering its entrance, according to a review of his disciplinary records at Souza-Baranowski Correctional Facility.

In addition, Hernandez did not have drugs in his system when he was found naked hanging from a bedsheet in his prison cell, according to a death investigation from Massachusetts State Police and the Worcester County district attorney.

Correction officers found Hernandez amid a gruesome scene, with drawings on the wall and "John 3:16" markings written in a substance consistent with blood, the investigation found.

The two reports, released to CNN in public records requests on Thursday afternoon, provide further details into the former NFL star's apparent suicide in prison in the early morning hours on April 19.

Jose Baez, Hernandez's attorney, said in a statement that the leaks of this information to the media cast doubt on the integrity of the investigation.

"The unprofessional behavior of those entrusted to impartially and professionally conduct an investigation into Aaron's death has caused grave concern as to the validity and thoroughness of the investigation," he said.

"Accordingly, we intend to fully, completely and impartially review all of the evidence in this matter."

Hernandez had been serving a sentence of life in prison for the June 2013 murder of Odin Lloyd. Hernandez's death came just days after he was acquitted of two murder charges related to a July 2012 drive-by shooting outside a Boston nightclub.

Cell had been blocked before

Hernandez was found dead at 3 a.m. when a correction officer noticed a sheet hanging in front of Hernandez's cell door and asked that he remove it or sound off, according to the report.

The officer poked at the sheet and it fell, revealing Hernandez hanged from a sheet tied to the window bars. Hernandez had "pegged" the door to his cell by stuffing its tracks with cardboard, making entry difficult, the report states.

He had obscured officers' view of his cell before. The prison disciplinary records detail an incident shortly after Hernandez was convicted of murdering Lloyd.

On May 17, 2015, a guard visited Hernandez's cell to check for marks and bruising following an alleged altercation.

"I ask for the cell door to open, but the inmate had the door blocked, making it difficult to open at first," according to a report of the offense.

He was accused of tampering with a locking device, and was disciplined with loss of 60 units from his canteen.

Two months later, a guard doing a cell check found a curtain hanging from the top bunk of Hernandez's cell. A curtain was also hung across the doorway, obstructing the view into the cell, records show.

Hernandez pleaded guilty to the offense and was docked 15 units from his canteen as discipline.

Blood drawings on wall

The night of his death, Hernandez had placed a large amount of shampoo on the floor to his cell, making it very slippery, according to the investigation report. Ligature marks were visible on his neck, and there was discharge and vomit coming from his nose and mouth areas, the report states.

The report also says that Hernandez's right middle finger had a "fresh" cut and that there was blood on his other fingers. In addition, there was a large circular blood mark on each of his feet and "John 3:16" was written on his forehead in ink.

No other signs of trauma were found on his body, and there were no signs of a struggle, the report states.

Underneath the drawings on the wall was a Bible open to John 3:16, with the 16th verse marked in blood, according to the report. Three handwritten notes, the text of which are redacted in the report, were also found next to the Bible.

John 3:16 is a reference to the well-known Biblical verse, "For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life."

1 a.m. cell check

Hernandez had been locked in his cell at 8:00 p.m. the evening before his death. At 1:00 a.m., a correction officer saw him during a cell check.

Surveillance video shows that no one entered or left his cell from 8:00 p.m. until he was discovered just after 3:00 a.m., according to the report.

Video also shows Hernandez had just gotten off the phone prior to being locked in the cell. The previous five phone calls he made that day did not give any apparent indication that he planned to harm himself, according to the report.

A postmortem toxicology test came back negative for all substances, including synthetic cannabinoids.