The murder of a Karachi school principal, which took place on December 9 in Karachi's Soldier Bazaar area, was committed by her husband, the case's investigative officer told DawnNews on Sunday.

After Ambreen Fatima was murdered, her husband Ali Hasan concocted a story about bandits shooting her during a robbery, said IO Sarfaraz Aryana.

However, when the police started investigating the case, they came across evidence of Hasan confessing to his wife's murder. The confession was made during a phone call between Hasan and Saher Shams, a school teacher who turned out to be his second wife.

According to Aryana, Hasan killed his first wife after the couple fought over his second marriage to Shams.

The IO said that Shams went on to relay the disturbing turn of events to her brother during a phone call.

According to Station House Officer (SHO) Rafay Tanoli, Shams was a friend of the deceased who had an affair with Hasan and then went on to secretly marry him.

"Shams was pressing Hasan for a ruksati now, which compelled Hasan to kill his first wife," the SHO said.

Police were suspicious of Hasan's narrative as there was sign of blacking on the temple of the victim, which indicated that the bullet was fired from very close range, the SHO said.

The police cracked the case by going through the phone records of all three suspects — Hasan, Shams and her brother — who have been taken into custody.

A similar case came to light on December 10 where a 20-year-old young woman killed her younger sister, Aleena, with the help of her fiance but initially covered it up with a fake story about a robbery attempt.

On December 6, it was reported that a 16-year-old girl was stabbed to death and her sister, Alveena, was wounded when they allegedly resisted a robbery attempt in their home.

However, Senior Superintendent Police (SSP) Korangi Nauman Siddiqui later told media that Alveena had confessed to slitting the throat of her little sister after allegedly being blackmailed by Aleena and her friends for several days.