Six teenagers questioned by police during their investigation into a spate of rock-throwing attacks were released without charge on Tuesday.

Police spokesman Lieutenant-Colonel Thulani Zwane confirmed that six boys were taken in for questioning but were not charged with any crime.

He added that there was insufficient evidence to link them to open criminal cases.

Amina Haffejee and her seven-year-old brother Abdhur Raheem were killed two weeks ago when a rock thrown from a bridge above the N2 near Tongaat‚ north of Durban‚ struck their car.

The rock ripped through the windshield and hit Amina - the force of impact causing her seat to fly back‚ hitting her brother.

A spate of similar attacks have followed‚ with a man injured on Saturday night when his car was hit by a falling rock in the same spot the siblings were attacked.

A reward of more than R250‚000 for information leading to the arrest of the attackers has been posted by the public.

A Ballito woman‚ Alicia Cilliers was travelling on the N2 when a group of men pelted her car with rocks last Thursday morning.

One of the missiles‚ which she maintains was aimed at her windshield‚ smashed her passenger window. She was alone at the time and continued driving.

The detention of the boys comes as the eThekwini Municipality moves to install steel cages around bridges to prevent further attacks.