Prosecutors stated there was inadequate proof from a fifth agent.
These named will now have 20 times to reply, and any demo will most likely be in absentia.
The Cambridge College pupil had been investigating unbiased trade unions - a delicate issue in Egypt.
Italian prosecutors named the four suspects - now set to generally be billed - as Gen Tareq Sabir, Col Ather Kamal, Maj Magdi Sharif and Col Hisham Helmy.
There was no speedy reaction from Egypt on the Italian allegations.
Egyptian authorities have Earlier denied that any of their officials had been linked to Regeni's kidnap and murder. They've instructed many other explanations - including that he was the sufferer of the theft by a legal gang.
And on one December they reported they were "temporarily closing" the investigation in to the murder, Along with the killer "continue to unidentified".
Regeni went missing in Cairo in January 2016 and his mutilated and bare entire body was found in a ditch in the vicinity of Cairo 9 days later on.
The murder induced a diplomatic row involving the two nations around the world, with Italian prosecutors accusing Egyptian officials of attempting to mislead the investigation.
"We've acquired unequivocal and important evidence," Rome Main prosecutor Michele Prestipino advised a information conference on Thursday.
"For Giulio's murder There is certainly just going to be a person demo, and it will be held in Italy."
he BBC's Rome correspondent Mark Lowen says any demo will throw a spotlight on Egypt's dire human rights record. Egypt's Fee for Legal rights and Freedoms states greater than two,seven-hundred people have been "forcibly disappeared" since 2015.
And it could prompt questions about a rapprochement with Italy's present-day govt, which not long ago accredited large arms sales to Cairo, our correspondent claims.
What happened to Giulio Regeni?
The PhD college student disappeared on a exploration trip on twenty five January 2016 - the fifth anniversary of the beginning in the rebellion towards former President Hosni Mubarak, indicating there was a hefty police existence in Cairo.
An Italian publish-mortem examination discovered that Regeni were tortured "in levels" amongst twenty five January as well as the day of his Loss of life.
His physique sustained accidents that confirmed he was crushed with "kicks, fists, sticks and clubs", and that he died from a damaged neck, official source prosecutors stated.
Egypt has denied that Regeni died in custody Despite the fact that officials have admitted that stability products and services were being monitoring him.
Egyptian investigators have previously advised that Regeni was go murdered by a 5-sturdy prison gang - and that every one of them ended up then killed inside a shootout. Italian officers have branded The theory "implausible".
Italian prosecutor Sergio Colaiocco explained to a parliamentary commission that Egyptian officers had created "faux stories... to throw from the investigation".
Other strategies put forward by Egyptian investigators were that Regeni died in an auto accident or simply a gay criminal offense of passion.
His physique was identified on three February in the ditch with the facet of the highway. His mom informed the Italian parliament in 2018 that her son's overall body was so disfigured that she was only capable of discover him via the idea of his nose.