The placard was seen in her hand on Monday evening during the protests in Mumbai to condemn the violence on the Jawaharlal Nehru University campus two days ago, triggered a political controversy.
Unfazed by Prabhu's apology, the Mumbai Police on Tuesday evening filed an FIR against her under Section 153(B) of the Indian Penal Code (IPC) for her indiscretion which snowballed into a big political row.
Kicking the ball, Bharatiya Janata Party (BJP) Leader of Opposition Devendra Fadnavis demanded to know what the protest was exactly about and why slogans of 'Free Kashmir' were raised there.
"How can we tolerate such separatist elements in Mumbai? 'Free Kashmir' slogan by Azadi gang at 2 kms from the CMO? Uddhavji (Thackeray) are you going to tolerate this 'Free Kashmir' anti-India campaign right under your nose???" Fadnavis tweeted on Tuesday.
Responding to the BJP charges, Shiv Sena Rajya Sabha MP Sanjay Raut made it clear that it would not tolerate if anyone talks of freedom of Kashmir from India.
"I read that those who held the 'Free Kashmir' poster clarified that they want to be free of restrictions on Internet services, mobile services and other issues. It doesn't mean that they advocate freedom from India," Raut told mediapersons.
Nationalist Congress Party Minister Jayant Patil retorted to Fadnavis that the 'Free Kashmir' poster was intended for freedom from all restrictions and discrimination.
On her part, the woman was identified as Mehak Mirza Prabhu, a Mumbai-born who works as a 'story-teller', said that though she had no agenda or motive, she was taken aback by the reactions on social media to the 'Free Kashmir' poster she carried on Monday night.
"The picture created by entire social media came as an absolute shock to me. The placard meant 'freedom to express themselves, freedom from the Internet lockdown which many people have been voicing for'. I was voicing my solidarity for basic Constitutional right. No other agenda or motive whatsoever," said Prabhu.
Reiterating that she was a Maharashtrian, born and bred up in Mumbai, she said: "I am (an) artist who believes in basic human compassion. If by being naive in understanding the impact it would have, and in the process create this stir, I apologise."
Prabhu urged all to let the 'power of love overcome hate', even as a Mumbai BJP-activist lawyer Vivekanand Gupta shot off a message to the Commissioner of Police demanding her arrest.
The Mumbai Police also filed three other FIRs, two against activists Suvarna Salve, Firoz Mithiborwala, Umar Khalid and others for unlawful assembly at the Gateway of India and for taking out a procession from Hutatma Chowk to Gateway of India without permission.
The police also lodged another FIR against student activists of Akhil Bharatiya Vidyarthi Parishad (ABVP) for carrying out a protest at Hutatma Chowk on Monday.
( With inputs from IANS )