A man discovered Oksana Makar wrapped in a charred sheet at a construction site on March 10 in Mykolayiv, the Kyiv Post reported.
The woman's kidneys were destroyed by the fire, more than 50 percent of her body was burned and both her feet and one arm had to be amputated, doctors told the Post.
Activist groups protested because although three men suspected of committing the crime were arrested, two of them were released before Makar made it to surgery, the newspaper said Friday. Protesters said the two men were released too soon and were shown leniency for their alleged crime because they are sons of local ex-officials.
The prosecutors office said it didn't have enough evidence at the time to hold the men, ages 21 and 23, although they were later arrested a second time March 13.
All three men have been charged with attempted murder, ABC News reported Saturday.