A man in his 20s is still being questioned about the murder of Daniel Aruebose, the child whose skeletal remains were found in Donabate in Dublin last year.
The man was arrested at Dublin Airport following his deportation from Brazil.
He is the second person to be detained in connection with the murder of the child who was last seen alive more than four years ago when he was three years old.
Gardaí are continuing to question the man at a garda station in Dublin.
He was arrested at Dublin Airport yesterday by detectives investigating the murder of Daniel, following his deportation from Brazil.
The authorities there said he was in "an irregular immigration situation" and he was deported.
The man was arrested on suspicion of the murder of the child who was last seen alive at his home in The Gallery apartments in Donabate when he was just three years old.
They commenced a search of waste ground near the child's home in Donabate and his skeletal remains were discovered after two and a half weeks.
The man is the second person to be arrested in connection with the murder investigation which is being led by a team of detectives at Swords and supported by specialist units including the National Bureau of Criminal Investigation.
His death and secret burial had been concealed until a check on social welfare payments first raised concerns at the Department of Social Protection, which alerted Tusla, who in turn contacted gardaí.
A woman in her 20s who was arrested last December on suspicion of murder was released without charge as the investigation into the child's murder continues.
The man, who knew both the woman and the Daniel Aruebose, can be questioned for up to 24 hours.
