New Delhi (CNN) -- Prosecutors on Wednesday urged a judge to sentence four men to death after they were convicted of the gang rape and murder of a woman in New Delhi last year.
"There can be nothing more diabolic than a helpless girl put through torture," public prosecutor Dayan Krishnan told the court.
He said the death penalty was justified because of the "extreme brutality" of the attack, which took place on a moving bus in December.
His request for the severest punishment echoes the views voiced by many Indians, including members of the 23-year-old victim's family, who have called for the men to be hanged.
Defense lawyers, meanwhile, argued for leniency.
"The court must bear in mind that life imprisonment is the rule and the death sentence is the exception," said V.K. Sharma, the lawyer for one of the convicts.
After listening to both sides, Judge Yogesh Khanna said he would sentence the four men on Friday afternoon.
Protesters demand hanging
As the prosecutor made his case for execution, the victim's father sat with his eyes half-closed.
The convicts stood at the back of the court, flanked by police officers on either side.
Outside the court building, protesters had gathered.
"We want justice! Hang the rapists!" they shouted after the judge said the sentencing wouldn't happen until Friday.
Some members of the group then barged into the court building but were then quickly chased out by the police.
After a trial that lasted about seven months, the Delhi court found the men guilty of murder, rape and kidnapping on Tuesday amid a heavy media and security presence.
The victim's parents had tears in their eyes as the judge read out the verdict, in which he said the men had been convicted of "committing the murder of a helpless victim." Her brother wiped a tear from his cheek.
The four men -- Vinay Sharma, Akshay Thakur, Pawan Gupta and Mukesh Singh -- will appeal the verdict, their lawyers said.
Outrage over the brutal, deadly assault had far reaching consequences in India. It fueled protests in various cities, started a discussion about women's treatment in Indian society and prompted the introduction of tougher punishments for sexual abuse.
Calls for executions
On Wednesday, the focus was on what the consequences would be for the perpetrators of the attack.
The father of the victim, whose name has been withheld under Indian law, has repeatedly called for the four men, aged between 19 and 28, to face the death penalty.
"We have faith in the judiciary. The accused should be hanged," he told CNN sister network IBN in an interview that aired Monday.
Family members are not alone in their desire for capital punishment. Calls for the execution of those responsible for the attack have been widespread in India.
Kiran Bedi, a human rights activist and former Indian police officer, said that a death sentence would send a "very powerful message" to a country bedeviled by sexual violence.
"A brutal crime gets absolutely severe punishment, so it's in proportion to the brutality of the crime," she said.
Death sentences issued by Indian courts have rarely been carried out in the past decade. No state executions took place in the country between 2004 and late 2012, when the last surviving gunman from the 2008 terrorist attacks in Mumbai was hanged.
But human rights advocates have said they fear that India's stance on executions has changed.
"In the past year, India has made a full-scale retreat from its previous principled rejection of the death penalty," Meenakshi Ganguly, South Asia director at Human Rights Watch, said last month.
Two others accused
The fate of two others accused in the case had already been determined before this week.
One man, Ram Singh, 35, was found dead in his jail cell in March. Authorities said he had hanged himself, but his family claimed he had been murdered.
A juvenile court convicted a teenage boy August 31 for his part in the gang rape, sentencing him to three years in a special juvenile correctional facility.
His trial was in juvenile court because he was 17 at the time of the crime, and the sentence is the maximum allowed under the court's rules.
The victim's mother said she was unhappy with the verdict and wants the teenager to be hanged.
A brutal attack
The brutality of the New Delhi attack, as described by police and prosecutors, helped stir the strong emotions surrounding the case.
On the evening of December 16, the victim, a physiotherapy student, had gone to see the movie "The Life of Pi" with a male friend at a New Delhi mall.
During their journey home to the suburbs, they boarded a bus at a major intersection in upmarket South Delhi.
The driver and at least five other men on the bus were drunk and looking for a "joyride," police said.
The men, from a poverty-ridden slum on the outskirts of Delhi, dragged the woman to the back of the bus and beat up her male friend.
Police say the men took turns raping the woman, using an iron rod to violate her as the bus drove around the city for almost an hour. When they had finished, they dumped the two victims by the side of the road.
The woman's injuries were so severe that some internal organs had to be removed. She died two weeks later at a hospital in Singapore.
"This is an extreme case of depravity" Krishnan, the prosecutor, said.
A rape every 22 minutes
As in many countries, rape is a grimly frequent occurrence in India.
According to Indian government statistics, a woman is raped every 22 minutes on average.
But the New Delhi attack seized the country's attention.
Advocates criticized the world's largest democracy for failing to protect half of its population. Protesters demanded better treatment of women and decried the apathy of police and the judicial system.
The government passed tougher anti-rape laws, introducing the death penalty for repeat offenders, and imprisonment for acid attacks, human trafficking and stalking.
But some Indians say that while the laws on crimes against women have changed, mindsets and enforcement have been slower to adjust.
'Take it to the source'
Government figures show that the number of women reporting rapes has risen significantly since the New Delhi attack and the heavy scrutiny that followed it.
Observers say it indicates that women who are victims of sexual attacks feel more emboldened to come forward than they did before.
Prosecution of such crimes has improved, Bedi believes, but it will take a heavy emphasis on the family and school environments to resolve the problem in the long run.
"You can't just begin and end with the police and the prosecution and the courts," she said. "You have to go backward and take it to the source."
CNN's Sumnima Udas reported from New Delhi and Jethro Mullen wrote from Hong Kong. CNN's Harmeet Shah Singh contributed to this report.