Iltija Javed, the daughter of former Jammu and Kashmir Chief Minister Mehbooba Mufti, released a second voice message on Friday, saying she has been detained at her home, days after her mother's arrest.
In a letter to the Union Home Minister Amit Shah, Iltija said that she has been "threatened with dire consequences" if she speaks to the media again.
"Kashmiris have been caged like animals and deprived of basic human rights," she wrote in her letter.
The shutdown in the Valley has entered its twelfth day, with top political leaders there remaining under arrest.
Along with Mehbooba, Omar Abdullah, senior National Conference leader and another former Chief Minister of the state, has also been arrested.
"Today while the rest of the country celebrates India's Independence Day, Kashmiris have been caged like animals and deprived of basic human rights," Iltija wrote in her letter.
She further added that she is not being informed when visitors are turned away from the gate and that she is not allowed to step out of her home.
Seeking an explanation from Shah over her detention, she alleged that security personnel cited her media interviews as the reason for it.
"I've been threatened with dire consequences if I speak up again," the People's Democratic Party (PDP) leader's daughter wrote.
"For the world's largest democracy, doesn't a citizen not have a right to speak up in the face of unimaginable repression... It's a tragic irony that I am being treated like a war criminal for stating the inconvenient truth," she wrote in her letter, which was released along with the audio message.
The voice message was released amid the communication crackdown in Jammu and Kashmir immediately after the abrogation of Article 370, which ended the state's special status and divided it into two Union Territories.
"I am being treated like a criminal and I am under constant surveillance. I fear for my life along with those Kashmiris who have spoken up," Iltija said in the audio message.
In her previous audio message, she said her mother is in solitary confinement without access to lawyers or party workers.
Mehbooba, along with Omar, was arrested and taken to 'Hari Niwas', a government guest house in Srinagar, on the night of August 5, immediately after the Rajya Sabha passed the Jammu and Kashmir Reorganisation Bill. Both of them have been placed under house arrest since then.
National Conference chief Farooq Abdullah and People's Conference leaders Sajad Lone and Imran Ansari were also arrested.
On August 14, former IAS officer and president of the J&K Peoples Movement Party Shah Faesal was sent back to Kashmir from the Delhi airport and detained in Srinagar under the Public Safety Act (PSA). He was shifted to a makeshift detention centre at the Centaur Hotel in Srinagar the next day.
Faesal was stopped from taking a flight to Istanbul at the Delhi airport and flown back to Srinagar where he was detained.
During preliminary questioning, Faesal said he was taking a connecting flight to London from Istanbul, the officials said.
(With Inputs from Agencies)