The accused killed three sisters and a brother of his sister-in-law in Rawalpindi.
A man with connivance of his brothers broke into the house of their sister-in-law and opened fire killing four people including three sisters and a brother
The police initially refused to register a case against but later booked Shaharyar Maher over court orders.
Most cases were decided by the model courts in Sindh and Khyber Pakhtunkhwa (KP) provinces.
A message thread shared on Twitter revealed that a student named Fatima was being threatened by a man named Ibsham.
The family of the deceased child claimed that the housemaid squeezed his throat and later murdered him by drowning in water after he watched her stealing the jewellery.
She earlier successfully tricked the aged man into naming her in his will.
The accused lives nearby Marwa's home and a piece of cloth helped the investigating teams in tracing the alleged culprit, said the police.
Remembering the brutality inflicted on an innocent 5-year-old Marwa, PTI lawmaker Siddiqui tabled an adjournment motion to call on lawmakers to debate.
The SSP East said that the parents of the victim had also cast suspicion over the death and termed it murder.