Charlotte Gallagher

I imagine a lot of people fear in Bangladesh that this could get worse.

And this murder, I know that there have been arrests, but have the police said what the motivations could have been?

and Barisan Etirajan.

Days after the mass shooting at Bondi Beach, the Australian Prime Minister has announced a national gun buyback scheme.

Antony Albanese said the authorities would collect and destroy hundreds of thousands of firearms, including surplus, illegal and newly banned weapons.

Our Sydney correspondent Phil Mercer has more details.

An international team of researchers have used drones to investigate the health of whales, uncovering a dangerous threat to their existence.

The whales were shown to carry a deadly virus which can be linked to mass strandings.

Our environment correspondent Helen Briggs explains how these findings were made.

Scientists have taken to the skies to study the health of whales in the wild.

Drones carrying scientific equipment were hovered over the giant ocean mammals to collect samples of their breath as they came up for air.

He also went out on boat to collect skin samples.

The test revealed vital clues about the health of humpbacks and other whales.

Researchers identified for the first time a highly infectious virus, one linked to mass strandings of whales and dolphins worldwide, affecting the animals in the Arctic.

Terry Dawson is Professor of Global Environmental Change at King's College London.

The drone technology is a real game changer in the ability to capture the blow samples from the whales and dolphins and through the analysis of those samples identify those diseases which obviously have huge impacts on the health and well-being of the animals and to understand why we're seeing these mass stranding events around the world.

Scientists hope this breakthrough will help them to spot other deadly threats to ocean life early before they start to spread.

Helen Briggs.

Finally, ever since the early days of the Beatles, Paul McCartney's signature instrument has been the Hofner violin bass guitar.

In 1961, the then 18-year-old bought the instrument in Hamburg for around $40, and it went on to feature on all of the band's first recordings, earning it the nickname The Beatle Bass.