Argentine investigator Alberto Nisman, in charge of investigating the 1994 bombing of the Argentine-Israelite Mutual Association (AMIA) building, was found dead at his home in Buenos Aires on Monday.

Nisman had last week accused President Cristina Fernandez de Kirchner and others in her government of covering up Iran's involvement in the terrorist attack.

Nisman's mother and bodyguards discovered his body on Monday in his Buenos Aires apartment, according to a press release from the Argentine security ministry. His bodyguards, members of the Argentine federal police, had grown worried when he did not answer phone calls or answered the home's door. They also noticed Sunday's newspaper had not been picked up.

Concerned, the guards contacted and picked up Nisman's mother who attempted to enter the residence only to find the door locked from the inside with key still in the lock. With the help of a maintenance man they entered the Nisman's home to find the investigator dead in the bathroom.

The security ministry reports the police secured the crime scene and retrieved a shell casing as well as a .22 caliber gun.

The Buenos Aires Herald reports Nisman was found with a bullet to the head.

Prosecutor Viviana Fein, in charge of the investigation, explained the head of the judicial morgue believes a third-party was involved in the incident. She is now awaiting lab results to determine if there was any gunpowder residue on Nisman's hands. If this is the case, it could suggest the AMIA investigator committed suicide. The analysis will also determine if the bullet matches the gun found alongside him.

In a later announcement, according to the BBC, it was determined there was "no intervention" in Nisman's death.

Prosecutor Fein has ruled out a robbery and noted there was no suicide note.

Nisman accused the president as well as her foreign minister, Hector Timerman, of covering up Iranian involvement in the AMIA bombing in exchange for oil. Argentina is currently experiencing an energy deficit, according to the New York Times. Nisman was to appear before a tribunal to report his findings on Monday.

However, the Kirchner government contested Nisman's claims. In a statement from the Argentine chancellery, Fernandez de Kirchner defends her work in the AMIA investigation and hints at wrongdoing on Nisman's part. The government alludes to some wrongdoing when noting that Nisman's accusations came after intelligence agent Jaime Stiuso was removed from the investigation.

The chancellery also argues Nisman wasted time in investigating President Fernandez de Kirchner instead of the real culprits, claiming the courts had not been informed of the investigation into the president.

Nisman's accusations last week tensed the nation's political scene as the country struggles with economic problems. The investigator had been in contact as late as Saturday with a reporter from the newspaper Clarin. During their communication, he told her, "I may be killed for this."