But 10 other activists they were with when police took them away on Thursday will be remanded till tomorrow.
Mrs K. Shanti and her daughter P. Vwaishhnnavi, together with the 10 activists, had tried to submit a letter to the Prime Minister's Office in Putrajaya. They were asking for the release of Hindraf's five leaders, detained under the Internal Security Act, ahead of Deepavali next week.
The letter was rejected by Prime Minister Abdullah Badawi's office. The Malaysian government banned Hindraf two weeks ago, declaring it an extremist group.
Kuala Lumpur police chief Muhammad Sabtu Osman later told news website Malaysiakini that the girl had not been arrested. She and her mother were released late on Thursday night but opted to stay on with the rest of the activists, according to the New Straits Times.
The girl's uncle, P. Uthayakumar, is one of the detainees while her father, Hindraf chairman K Waythamoorthy, had earlier fled to London to escape arrest.
The girl has been a familiar face at Hindraf's protests. On Thursday, she was seen toting a poster that said 'Release Our Leaders'.
Police Watch Malaysia coordinator S. Jayathas, one of the 10 arrested, claimed that the group was taken away after being told that they formed an illegal assembly.
'We were trying to obtain permission from the security guards for Vwaishhnnavi to submit her letter. They said that we were from Hindraf, but we insisted that we were 'concerned Indians' ...accompanying Vwaishhnnavi,' he said.
Yesterday morning, the 10 activists were taken to the Kajang magistrate court. Security was tight - police barred journalists and supporters from entering the building, allowing in only family members and the lawyers of those arrested.
According to lawyer N. Surendran, the activists are being investigated for participating in an unlawful organisation. The New Straits Times also said that Mrs Shanti is being investigated for child abuse.Six-year-old 'protester' walks free
Straits Times, Singapore