Punjab police of Wednesday arrested three suspects in connection with the murder of a retired female professor from Ahmadi community and said robbery was a motive rather than hate, in a statement released.

The professor, Dr Tahira, used to live alone in her house in the Punjab University Housing Colony. The husband of the deceased professor had died earlier, while her only daughter lived in Karachi.

When officials first received the report, they entered the house Tuesday morning and found the retired professor's body lying in a pool of blood.

The initial investigation suggested there was no sign of a break-in or a robbery.

However, when police officials traced down Dr Tahira's cell phone on the complaint of her daughter ─ who had said her number had been non-responsive ─ they caught the suspects red-handed while they were trying to sell the device.

Upon arrest, police claimed Sajjad Ali, the main accused in the case, confessed to killing the retired professor.

Ali, an employee of Punjab University. was called by the professor to fix a ceiling fan in her house, the police statement added.

Ali then visited the retired professor with a plan to commit a robbery as he was aware that she lived alone and stabbed her when she caught him attempting to steal an iPhone and cash. The accused then fled the scene, elaborated the police statement.

Police officials said it was then that the accused stabbed Dr Tahira with a paper cutter and fled the scene. Further investigations in to the case are being conducted.