Media playback is unsupported on your device Media caption Footage released by police shows suspected gunman

New footage showing the suspected killer of journalist Lyra McKee moments before she was shot has been released by police.

The 29-year-old was hit by a bullet while observing a riot in the Creggan area in Londonderry.

Det Supt Jason Murphy said he believed the man in the images to be in his late teens, relatively short in height and with a stocky build.

The gunman is one of three men seen in the footage.

He first appears on the left of the screen, walking with another masked man.

In one of the images, the man appears to have a gun in his right hand.

Earlier this week, the New IRA said its members had carried out the killing.

A reward of up to £10,000 has been offered for information by the charity, Crimestoppers.

BBC I believe the community has the information to help me unlock the key to Lyra McKee's murder."

On Friday, Det Supt Murphy appealed for anyone who recognises the men in the images to come forward and tell police.

"I believe the community has the information to help me unlock the key to Lyra McKee's murder," he said.

"I recognise people living in Creggan may feel it's difficult to come forward to speak to police.

"I want to provide a personal reassurance that we are able to deal with these concerns sensitively."

Analysis: Mark Simpson

One week into the police investigation, detectives still have not recovered the weapon used in the attack.

They are pleased that more than 140 people have provided them with information, but they need more.

Forensic tests on the bullets fired suggest a weapon of similar calibre had been used in previous paramilitary-style attacks in the area.

What detectives are doing now is piecing together the scientific and visual evidence, comparing it with witness statements, and seeing where it leads.

The killing of Lyra McKee has kick-started Stormont talks which could potentially break the political deadlock.

Police have their own job to do. And like the politicians, they have a long way to go.

They are relying on the public for more information.

Pictures of two other men, seen walking alongside the gunman shortly before the shooting, were also released.

Image copyright Psni Image caption Police are appealing to anyone who recognises the man in the image, seen carrying a crate of petrol bombs

One is seen carrying a crate of petrol bombs, while the other is described as wearing dark skinny jeans, blue Nike trainers with a white tick and a white sole.

He is also seen wearing a camouflage scarf or other covering across his face.

Image copyright Psni Image caption The man highlighted is seen wearing dark skinny jeans and Nike trainers with a white tick and white sole

Police say more than 140 people have provided images, footage and other details through the dedicated Major Incident Public Portal.