Jayleigh Murray - then aged 11-months-old - was found unresponsive at her home on Aldrin Avenue in Dubbo about 6.20pm on June 6, 2019.

She was treated at the scene by NSW Ambulance paramedics before she was taken to Dubbo Hospital. The baby was later airlifted to the Children's Hospital at Westmead, where she died on June 12 - just 12 days short of her first birthday.

On Wednesday, Investigators from the Child Abuse and Sex Crimes Squad released footage of a man seen walking in front of Jayleigh's house in Aldrin Avenue, just after 6.05pm on June 6, 2019.

Police have stressed the man is not a suspect, but believe he may have seen or heard something that could assist the investigation.

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The man depicted in the CCTV is described as being aged in his 20s, thin build, about 150cm tall, and was seen wearing dark coloured pants, a grey hooded jacket with white stripes on the sleeves, and a grey coloured cap.

Strike force detectives are urging the person seen in the CCTV to come forward and help with their investigation into Jayleigh's death.

A post-mortem examination revealed the toddler suffered from a non-accidental head trauma and other suspicious injuries before her death.

Detectives established Strike Force Binara to investigate the circumstances surrounding the incident.

Despite extensive investigations, no one has been charged in relation to Jayleigh's death.

On Monday, investigators offered a $250,000 reward hoping it would prompt people in the community with information to speak with investigators.

Investigations under Strike Force Binara continue.

Anyone with information that may assist Strike Force Binara investigators are urged to contact Crime Stoppers on 1800 333 000 or at nsw.crimestoppers.com.au.

Information is treated in strict confidence and the public is reminded not to report information via NSW Police social media pages.