In a separate incident in the Belgrano neighbourhood, a 26-year-old man was arrested after throwing an explosive device onto the home of Claudio Bonadio, the federal judge that has headed a number of high-profile investigations including six involving former president Cristina Fernández de Kirchner.
The man, identified as Argentine national Marcos Nicolás Viola was arrested after throwing a bag containing pipes and explosive elements into the perimeter surrounding Bonadio's home. The man reportedly fled the scene and was chased down by police. Buenos Aires City Police later detonated the device in a controlled explosion and carried out searches of the property.
The incidents come just two weeks before world leaders converge on Buenos Aires for the G20 Leaders Summit.
President Mauricio Macri told Radio Don de La Pampa that those responsible for the law "are going to pay the consequences."
A 33-year-old woman and her partner, who was identified as Hugo Rodríguez, were arrested at the crime scene in Recoleta on Wednesday.
The woman was later hospitalised at the Fernández Hospital suffering from serious injuries, including burns, the loss of three phalanges and wounds to her face, SAME ambulance service director Jorge Crescenti told the TN news network. Officials later said she was in a coma.
Police reported the pair had entered the cemetery wearing wigs. The woman, who entered in a wheelchair, was carrying five explosive devises when she was stopped by police. The devices were then detonated.
It is believed the attack was planned against the tomb of Coronel Ramón L. Falcón, who was murdered 109 years ago today by Ukrainian militant anarchist Simón Radowitzky.
Falcón, who was born in 1855, is remembered for having ordered the ferocious repression of an anarchist demonstration on May 1, 1909 in Buenos Aires, violence in which a dozen people dead, and for the subsequent persecution and arrest of those who followed that ideology, in an episode known as "Red Week."
Falcón was assassinated on November 14, 1909 by Radowitzky, an anarchist militant who sought revenge for those actions. Radowitzky was sentenced to life imprisonment and pardoned after 21 years in prison.
Buenos Aires City Security Minister Marcelo D'Alessandro said Thursday that authorities were confident the suspects "are tied to anarchist groups." He described the bombs as "quite sophisticated."
"The explosives department has determined that not only that it was a bomb, but even though it was homemade, it was quite sophisticated, in which three detonations were made. It was a pipe[-bomb] but with greater sophistication and power, according to experts," D'Alessandro told the TN news channel.
He added that the timing was not coincidental.
"Despite the precariousness of the devices they put together, these are dangerous groups which we must pay attention to even if they are small groups," D'Alessandro told the La Red radio station in later comments.
"We have to investigate this completely because the incident at [the cemetery of] Recoleta highlights the level of danger of these devices and bomb [thrown into Bonadio's property]. They could have caused greater harm," he added.
"Nothing is coincidence or coincidence. We are on the eve of one of the most important international event, which is the G20 summit. We have examples of what has happened in other cities and we are working to provide the necessary security, but without a doubt it has a connection with respect to that," said D'Alessandro.
Ten more people were arrested at an abandoned apartment in the San Cristobal neighbourhood, in downtown Buenos Aires, on Wednesday evening. Security Minister Patricia Bullrich said material similar to the explosive devices was found onsite. She blamed both attacks on people with "an anarchist orientation."
Police raided what they believe is a squatter's home on orders of Federal Judge Julián Ercolini, where they reportedly seized wicks, gunpowder and pipes similar to those used in the attack.
We have seized fuses, powder, pipes, grinders and nails," Federal Police Chief Néstor Roncaglica told reporters.