Ukraine rape scandal victim Oksana Makar dies
Three men were arrested, but two - whose parents had political connections - were released without charge.
They have since been re-arrested, after the case prompted a national outcry.
Interior ministry spokesman Volodymyr Polischuk told a news conference on Thursday that all three men, aged 22 to 24, now faced charges of rape and murder. He said they could face life sentences in jail.
Ms Makar lost consciousness after her attackers abandoned her at a construction site and set fire to her.
She was eventually found the next morning by a stranger and taken to hospital in Mykolayiv with 55% burns.
AnalysisOksana Makar's murder has prompted Ukrainian society to confront what have become known as "bigwig crimes" - offences committed by the children of public officials and, at times, by officials themselves.
As a rule, they are either given a suspended sentence or escape punishment entirely.
In January, Roman Landik, a member of Luhansk city council and the son of a Ukrainian MP, was sentenced to three years' probation for punching a girl in a Luhansk restaurant.
Protesters across Ukraine are demanding justice and an end to legal abuses by "bigwigs".
President Viktor Yanukovych has instructed Ukraine's attorney general to investigate Oksana Makar's case.
Interior Minister Vitaly Zakharchenko has stated that the parents of two of the suspects are former government officials in the Mykolayiv area.
Ukrainian media have shown footage of one of the three suspects describing to police how Ms Makar was attacked in a flat in the city and then wrapped in a blanket and left in a pit.
The victim's mother posted a video of her lying in her hospital bed, in which some of her appalling injuries were visible.
The Kiev Post described the attack as "one of Ukraine's most heinous crimes in recent years".
There have been several protests in Mykolayiv and elsewhere in Ukraine, including Odessa, Lviv and Kharkiv.
The case has led to the Communist Party, which is part of the ruling coalition in parliament, to highlight its call for a return to the death penalty.