reports.
Prosecutors said the case is being investigated as a femicide.
The suspects have been sent to undergo medical tests before appearing in front of the judge who ordered their arrest.
Fatima was reported as missing on Tuesday 11th February and her body was found in the municipality of Tlahuac inside a rubbish bag in a wheelie bin four days later, according to local media.
But authorities lost a full day in the search for because they waited for a formal missing-person case file to be opened.
The cause of the girl's death is yet to be released and the investigation continues.
'FEMICIDE STATE'
The lower house of Mexico's Congress held a moment of silence Tuesday for Fatima, whose case has sparked a wave of protests and outrage.
Congress also signed off on an increase in prison sentences for crimes of femicide and sexual abuse of minors.
Lawmakers voted to increase the sentence for femicide to 45 to 65 years in prison, up from a range of 40 to 60 years.
They also have their approval to toughen penalties for sexual abuse of minors to 10 to 18 years, up from six to 13 years.
The proposals will be sent to the Senate.
Protester also took to the city's streets, marching from president's house to the offices of La Presna, the newspaper that published the gruesome image.
The furious demonstrators daubed the walls of Mexico's national palace in blood-red paint, scrawling "femicide state".
Ten women are killed a day in Mexico and victims of femicide are on the up.
The senseless killing sparked huge protests across Mexico after 25-year-old student, ingrid Escamilla was stabbed to death and skinned by her husband.
The horrific murders happened just two days apart.
Protests have swept Mexico City, with activists branding signs with the girls' faces on and the hashtag #JuticiaParaFatima, meaning Justice for Fatima became a top global trend.
Forensic workers leaked pictures of Ingrid Escamilla's corpse to the press sparking outrage as the rate of violent crime against women continues to rise in the country.
President Andres Manuel Lopez Obrador has insisted the spiralling epidemic of violence against women in the country is down to: "A progressive degradation that has to do with the neo-liberal model".
He also blamed “social, family problems” and called the incident a “social disease”.
Critics say he is blaming his predecessors for Mexico's issues instead of using his time in office to "prove he is different".
In his first year as President, femicide rose by ten per cent.
Mexican President under fire after brutal murder of girl, 7, sparks widespread protests across the country