The family of Mahsa Amini are being held under house arrest at their home in Iran, her cousin has confirmed to The National.
Amini's parents and her brother have been “detained in their home” by authorities since Wednesday, Erfan Mortazei said, speaking from the Kurdish region of Iraq.
Thousands of people on Wednesday descended upon the cemetery in the city of Saqez where Amini's grave is located to mark 40 days since her death. Security forces opened fire on mourners gathered at her gravesite in the Kurdish city.
On Tuesday, state media released a purported statement from Amini's family saying they would not be holding a remembrance ceremony the following day. Mr Mortazei said this statement was written by authorities and it was immediately rejected by the family.
Her brother has been threatened with arrest in recent days, he added.
“Zhina and thousands like her sacrificed their lives so that the Iranian people could live in freedom,” said Mr Mortazei, referring to Mahsa by her Kurdish birth name. “I hope the Iranian people will continue to take to the streets until they achieve their goals.”
Amini has become the face of the fiercest protests Iran has seen in decades, sparked by her death in morality police custody in September.
Rights groups say at least 141 people have been killed, including 29 children, in the nationwide demonstrations.
The family do not feel free to mourn Mahsa, her cousin said.
Her brother last visited Amini's grave on Monday, but security forces have been a “nuisance”, he added.
“They are always making trouble.”
On Thursday, large crowds gathered at the grave of 16-year-old Nika Shakarami in Khorramabad to mark 40 days since her death.
Rights groups said live ammunition was also fired at hundreds of people gathered at the cemetery in Lorestan province.
The teenager was killed after attending protests in Tehran. While authorities have said she fell off a building, her mother has publicly rejected those claims, saying her daughter was killed by authorities and the family pressured into silence.