Story highlights The remains of former Brazilian President Joao Goulart are being studied

There are suspicions about how he really died

He was given full state honors at a ceremony Thursday

Other Latin American leaders have also been exhumed for similar reasons

Full funerary state honors were bestowed upon former Brazilian President Joao Goulart for the first time Thursday, nearly 37 years after his death.

Goulart, who was president from 1961-1964, was deposed in a coup and died in exile. The ceremony in the Brazilian capital provided the proper official ceremony to which deceased heads of state in Brazil are entitled.

President Dilma Rousseff placed flowers on top of the casket and presented the flag that had been draped over it to Goulart's widow.

But the remains of the former president were exhumed for purposes other than a funeral ceremony.

Goulart died in exile in Argentina of a heart attack in 1976, but there have long been suspicions that he was murdered. Poisoned, to be exact.

The former president's body was exhumed so that investigators in Brazil and abroad can study the remains in hopes of clarifying how he died.

"It is Brazil's duty to clarify the circumstances surrounding the death of President Joao Goulart," said Maria do Rosario, Brazil's secretariat of human rights.

Other South American leaders have recently been exhumed for similar investigations.

In 2011, the remains of former Chilean President Salvador Allende were disinterred over questions about his death. A court studied the results and ruled that Allende indeed had committed suicide

In Venezuela, investigators studied the remains of revolutionary leader Simon Bolivar, but were unable to determine the cause of his death. They did, however, recreate a 3-D image of his face

According to the Brazilian government, there are suspicions that Goulart was poisoned on orders of the Brazilian military government with the help of the Uruguayan military through Operation Condor, an alliance between the military dictatorships in the Southern Cone at the time.

Last year, the media reported on intelligence documents that showed that the military government spied on Goulart even after he left the country.

After being ousted from the presidency, Goulart went to Uruguay, and later Argentina.

The first requests to have the former president's remains exhumed came from his family in 2007, the government said in a news release. The request received the backing of the human rights secretariat in 2011, and the exhumation was finally given the green light in 2012.

The intent is to combine the forensic analysis with testimonies and government documents to paint a complete picture surrounding his death.

But on Thursday, it was a moment of honor and ceremony for the president who was popularly known as "Jango."

In addition to Rousseff, three former presidents were also in attendance.