NEW DELHI -- Indian lawmakers voted Tuesday to lower to 16 from 18 the age at which a person can be tried as an adult for heinous crimes following anger over the release of one of the attackers in a fatal 2012 gang rape.

The man was short of his 18th birthday when he and five other men brutally raped a 23-year-old woman on a bus in the heart of the Indian capital. She later died in a hospital.

The young man served the maximum sentence of three years in a reform home and was released Sunday. Four men convicted of rape and murder were sentenced to death and are appealing their sentences in India's top court. A fifth man died in prison.

Tuesday's vote in the Rajya Sabha, or upper house of Parliament, followed a vote in May in the more powerful lower house, Lok Sabha. The amended law needs to be signed by India's president before it becomes a law.

The outrage over the Delhi attack prompted quick action on legislation doubling prison terms for rapists to 20 years and criminalizing voyeurism, stalking and the trafficking of women.

It also started a heated debate about whether minors who commit especially brutal crimes should be tried as adults.

The parents of the victim of the 2012 attack watched the hourslong debate in Parliament from the gallery Tuesday. They had led the protests demanding new and tougher law for juvenile offenders.

Minister for Women and Child's Right, Maneka Gandhi, who proposed the amended law, said that a "more nuanced and compassionate" law was not possible.

But several lawmakers also asked that the law be sent to an expert committee and more children's rights experts weigh in before the changes were made law.

In the end however the bill was passed swiftly with most members present voting in favour of the changes.

The amended bill says defendants between 16 and 18 years of age can be tried as adults for all crimes carrying possible penalties of more than seven years in prison. These include murder, rape, kidnapping and acid attacks.

However for a minor to be tried as an adult the local juvenile justice board would have to assess the offender and decide if the minor could be tried as an adult.

Minors who are convicted as adults would stay in a reform home until they turn 21 then complete their sentences in a regular prison.

A special court would also put together a rehabilitation plan for the juvenile offender after the prison term was served.