Media playback is unsupported on your device Media caption The father of the drowned girl says he made 'a big mistake'

A man in Pakistan who confessed to drowning his one-and-a-half year old daughter says he now regrets his actions. His family says it was because he wanted a son, but it highlights the grave issue, across South Asia, of female infanticide. The BBC's Aleem Maqbool met the family in Lahore.

We meet 28-year-old Umar Zaib as he waits, shackled, outside court.

"It was a mistake," he tells me. "I made a big mistake. I don't know what was going through my mind when I did it."

Umar Zaib is talking of the crime he committed against his daughter, Zainab, who was just one-and-a-half years old.

Then the police jostle him and push him towards the courtroom. He is under arrest and yet to be charged but has admitted to the police that he drowned his daughter.

He insisted it was all because of a fit of rage. But when she described the horrors of what happened, Umar Zaib's wife told us a very different story.

"It was late at night but my husband told me we all had to visit his sister, but we stopped close to the river," says Sumera, 24.

"I had both our daughters with me. My husband told me I wasn't holding Zainab properly and he took her from me."

"In front of my eyes, he threw her in the river."

"I was helpless, I started crying, Zainab was screaming in the water but when I tried to save her he beat me."

Pleading for help

On the outskirts of Lahore, we visit the place beside the powerful River Ravi where Umar Zaib has now told investigators he killed his daughter.

On the Ravi Bridge towering over the spot, devotees hurl meat for the flocks of carnivorous birds that circle close by, hoping for blessings in return.

Image caption Sumera: " "I had both our daughters with me... In front of my eyes, he threw her in the river."

This dirty bankside, where the stench of the brown waters mixes with that of rotting meat, is where Sumera says she last saw little Zainab struggling and pleading for help.

A short distance downstream, we find two divers still looking for her remains in the fast-flowing waters.

They are ill-equipped, and admit to us that so long after the event they have all but lost hope of finding Zainab's tiny body.

Sumera says her husband threatened to kill her as well if she told anyone, so for several days she was too scared to go to the police. But finally she found the courage to tell her parents.

He has forgotten her already and he told me she's gone where she is supposed to go Sumera, Zainab's mother and Umair's wife

They will now support their daughter and her young baby.

Sumera says she is certain of her husband's motive in killing their daughter.

"Since our first daughter has born, he wasn't happy, he wanted a son," she tells us.

"He said if I had another daughter, he'd kill our first child, Zainab. When, eight weeks ago, I did have another girl, he kept threatening more and more, then he did it."

She says her husband, a rickshaw driver, and his extended family all looked down on female children, thinking them a curse, but she says their family was not alone.

"My life is empty without Zainab," she says. "But he has forgotten her already and he told me she's gone where she is supposed to go."

Cultural pressures

Image caption Divers have been looking for the body of Zainab in the river where she disappeared

The disturbingly prevalent tendency, across this region, to kill babies purely because they are female has been well-documented.

The United Nations Children's Fund, Unicef, has a team dedicated to the issue in Pakistan.

It says girls are murdered primarily because of cultural pressures and poverty.

Coming soon: Throughout October the BBC will be shining a light on the risks, challenges and opportunities women around the world face today. Find out more about the 100 Women season

But for years, rights groups in Pakistan have also accused law enforcement agencies of not taking the issue seriously.

"Yes, of course cases like that happen in Pakistan," says Basharat Ali, the investigating police officer in Zainab's murder case.

But then he suggests that Zainab's mother has questions to answer too.

"How can a mother, who sees someone else throw her daughter in the river, just leave quietly and not report it for a week?"

He may be behind bars now, he may even have admitted to killing his daughter, but in Pakistan there are no guarantees Umar Zaib will be properly punished for killing his child, apparently just for being a girl.