Mykola Chynchyn, head of the ministry's investigative department, said Friday investigators were following several leads in the attack on the investigative reporter after she had posted photos online of what she said was a top government official's luxury estate, Interfax-Ukraine reported.
Chornovol also reported on Ukraine's protest movement, which has grown since November after, President Viktor Yanukovych backed out of political and trade agreements with the European Union.
Her vehicle was forced off the road early Wednesday, police said. She was dragged from the car and beaten, and left in a ditch. She was hospitalized with a concussion.
The ministry said one lead indicated a suspected assailants may have been involved in the company that took over the TVi channel, considered Ukraine's only independent television channel, while another suggested people tied to crime organizations may have been involved.
The U.S. State Department expressed concern over what it called "an emerging pattern of targeted violence and intimidation toward activists and journalists" who have participated in or covered protests arising from Yanukovych's decision.
"We urge the government of Ukraine to send an unequivocal message that violence against critics of the government and those who are working toward a modern, democratic, and prosperous Ukraine will not be tolerated," the department said in a statement, calling Chornovol's beating "particularly disturbing."