Chief Prosecutor Vincenzo Verzera will ask the judge to rule that the man be held in pre-trial custody in prison, Ansa reported.
The man was arrested on Sunday after the bodies of Victor Solano, 68, and his 70-year-old Spanish wife, Mercedes Ibanez, were found at their home near the Cara Mineo refugee centre, outside Catania, where the suspect had been staying.
Solano was found with his throat slit while his wife's body was found in the courtyard beneath their apartment. It is believed that she fell from the balcony.
Citing a judicial source, Ansa reported on Tuesday that an initial autopsy showed that Ibanez may have been raped.
The report is expected to be filed to prosecutors by the end of today, while a full autopsy report will be filed within 60 days.
The couple will be buried on Wednesday, Corriere reported.
The suspect was implicated in the double murder after a phone and laptop, allegedly belonging to the victims, were found in a bag he was carrying as he entered the refugee centre. He claimed he found the bag in the street.
Blood-stained trousers, thought to belong to the suspect, were also found in the garden of the couple's home.
The suspect was also allegedly wearing a T-Shirt belonging to Solano, which was recognized by the deceased man's daughter, at the time of his arrest.
His arrest flared the debate over migrants in Italy, with Matteo Salvini, the leader of the anti-immigration Northern League party, writing on Twitter and Facebook on Monday: “From what war was this guy escaping??? If he's guilty, jail for life, with HARD LABOUR!”
Other politicians, including Sicilian President Rosario Crocetta, have called for the centre in Mineo – the largest of such facilities in Europe – to be closed.
“It will never work...it's the wrong model,” Crocetta said.
“You can't put three to four thousand people - without prospects or ties to the territory - together in one place.”
Premier Matteo Renzi has so far stayed silent after the couple's daughter, Rosita Solano, blamed the government for the murders, saying it allowed “immigrants to come here and do what they want, even rob and kill us.”
On Tuesday, she told Corriere that neither the premier nor Angelino Alfano, Italy's Interior Minister, had even Tweeted a message of support.
“My parents didn't even merit a tweet,” she said.
“I want justice – not political controversy: Renzi come and speak to me, show your face...before the funeral. When he was nominated premier, I thought Italy would finally be worth something in Europe, instead...”