Detectives investigating the death of a pensioner following a burglary at her flat have released CCTV images of two young boys on bikes who could hold the key to finding her killers.

Maureen Whale, 77, died after a break-in at her home in Barnet, north London, due to coronary heart disease which the coroner ruled on Friday was brought on by stress from the incident on December 4.

Police are treating her death as manslaughter.

Officers said the boys on bikes in the CCTV are not in any trouble but are "potentially really important witnesses".

An image of a missing small brown wallet, also released on Tuesday, shows it was used by Ms Whale earlier in the day while out shopping.

Detective Chief Inspector Noel McHugh, of the Metropolitan Police, said: "We really need the public's help. So far few people have come forward. We are still keen to trace two young white lads, aged around 12 and 15, on bikes in the Bells Hill area at that time.

"They are thought to be local and approached and spoke to the first officers on the scene. They are potentially really important witnesses and I would urge them to get in touch.

"If you are nervous about contacting police, speak to a teacher, parent or trusted adult but you are not in any trouble."

Officers will be in Barnet on Tuesday to hand out leaflets and speak to passers-by and drivers between 4.15pm and 6.15pm, to appeal for more witnesses and information.

In a joint statement, Ms Whale's nephew Lawrence and her niece Gina said: "It is heart-breaking that our Aunt Maureen is no longer with us; this last week has felt like a nightmare.

"She should have been safe in the house that she lived in all her life and we now ask how this could of happened? The last thing she or anybody else would have ever expected, is for burglars to break in whilst she was at home.

"This must have been a truly terrifying ordeal for her. All we think about now, is of how vulnerable and scared she must of felt."

Ms Whale called the police at 6.01pm on Tuesday December 4 after two individuals broke into her home before stealing jewellery and her handbag.

While on the phone to the police, Ms Whale collapsed.

She was taken to a north London hospital in a critical condition but died the following morning.

The incident is being linked to two more burglaries on the same road which took place at around 5.35pm, as well as another on Sampson Avenue, Barnet, at around 11.45am on the same day.