Two suspects have been arrested for the killing of 42-year-old Mariano Barbieri last Wednesday night in Palermo, according to police sources.
The Buenos Aires City Police has two individuals in custody, one of whom matches images from security camera footage close to where the incident took place, they added.
One man, 29, was detained by officers in the Villa 31 shantytown in the Retiro neighbourhood. Police believe he is the suspect who stabbed Barbieri while he attempted to steal the victim's mobile phone.
Police provided no information about the second individuals, only saying that he had been arrested at around midday.
Investigators are making progress as they attempt to paint a full picture of the night's events.
At least one witness has reported seeing two individuals in the vicinity close to the hour at which the attack took place.
A knife believed to have been used in the attack is undergoing DNA testing to identify if the blood on the weapon is Barbieri's and whether fingerprints can match a suspect to the crime.
Thee attack occurred on Wednesday night as the 42-year-old engineer was walking at Plaza Sicilia in Palermo. After being attacked he managed to walk 300 metres before collapsing on the floor of a nearby ice cream parlour where he called for help. He was rushed to hospital via ambulance but eventually died.
The engineer's murder sent shockwaves through capital. City Mayor Horacio Rodríguez Larreta decided to change the leadership at the helm of the Security & Juistice Ministry, replacing Eugenio Burzaco with Gustavo Coria.