Around 30 women, many of whom were wives of jihadist recruits, were flown back to Pristina on Saturday alongside 74 children and four men.
The men were charged upon arrival with participating in a foreign conflict.
"We had launched investigations into the women before, but they had to be suspended because they were inaccessible," Special Prosecutor Syle Hoxha told AFP.
"Now we have new testimonies about their activities in Syria obtained by the police following their return on Saturday and the investigations have formally been relaunched," Hoxha added.
The families have been released after initially being held in a migrant centre outside Pristina over the weekend.
In total some 300 Kosovars out of a mostly-Muslim population of 1.8 million joined jihadists in Iraq and Syria, making Kosovo one of Europe's highest per capita contributors of foreign fighters to the conflicts there.
Around 70 died abroad and an estimated 120 have come home, with most arrested on their return.
Countries around the world have been grappling with how to repatriate citizens who fought with the Islamic State group, including children and wives of militants who want to return.
In March France for the first time brought home five children amid massively hostile public opinion.
Police believe that around 30 Kosovar fighters are still in Syria, as well as some 50 women and children.
Four years ago Kosovo passed a law allowing citizens to be jailed for up to 15 years if they leave the country to join armed groups abroad.
