The incident took place on Wednesday when Shanta Machindra Shinde (40) of Kalamb from Osmanabad came down to Thane along with her minor daughter Ripa for attending a hearing in the local court in a case involving her brother Balu Pawar, they said.
The girl went "missing" from near Ambedkar statue outside the court around 10 AM, when the mother went to drink water leaving her behind before the proceedings, police said.
But when Shanta returned to the spot, she could not find the girl. After searches all through the day, she filed a complaint of kidnap by unknown persons with the police yesterday.
Thane Nagar Police said an offence under Section 363 of the IPC has been registered in this connection.
On the day of the alleged kidnapping, the mother-daughter duo had first visited Pawar lodged in the Thane Central Jail and then they came to the court for the hearing.