Investigators say they are “one phone call away” from finding those responsible for a house fire that killed an innocent Melbourne woman earlier this year.

Katie Tangey, 27, was housesitting for her brother and his wife at their property in Melbourne’s west in Truganina on January 16.

About 2am, two people were captured on CCTV getting out of a dark coloured vehicle – similar to a BMW X3 or X5 – and parking outside the address, police say.

A “significant explosion” then occurs and the pair then fled the area, carrying what is believed to have been a jerry can.

Tangey, who was inside the house at the time, called triple zero but died at the scene along with the family’s golden retriever.

The three-storey townhouse was completely destroyed.

Detectives believe the arson attack was likely linked to the illicit tobacco dispute, and was a targeted attack but at the wrong address.

“Investigators know Katie was completely innocent and had nothing to do with the illicit tobacco trade,” police said in a statement.

Investigators also believe exiled tobacco kingpin Kaz Hamad orchestrated the botched hit from overseas, but the arsonists torched the wrong home.

“We know we’re one phone call away from cracking this investigation,” Arson Squad Detective Inspector Chris Murray said.

“Unfortunately the two… the only word I can use is two buffoons who did this act, they targeted the wrong address.”

Police are now calling on the crime world for help, with a $500,000 reward for any information announced today.

“I’d suggest even they’d be disgusted at what’s happened here,” Murray added.

In April, investigators released a digital composite image of a man they would like to speak to in relation to the investigation.

The image of the man’s face was compiled using CCTV footage which has been enhanced.

He is described as Middle Eastern in appearance, aged between 25-30 years old and with a slim build.

Police said they had received some leads via anonymous reports to Crime Stoppers, including one call where a name has been given of a pseudonym or nickname.

Investigators are still urging this particular caller to make further contact and provide additional information.

“These two faceless and gutless individuals that carried out this attack, we just need some names to those faces,” Murray added.

Detectives are particularly keen to hear from anyone who recognises the man in the image or has any further information on the nickname provided.

“We believe we know who directed this crime, and we know we are getting closer to proving who was responsible for carrying it out on the night,” Murray added.

“Those responsible for Katie’s death know they targeted the wrong house and they have to live with the knowledge that they are responsible for the horrific death of a completely innocent young woman. 

“$500k is a lot of money – hopefully it will encourage those people out there who do know something to do the right thing and come forward.

“Katie’s family deserve answers.”

A reward of up to $500,00 will be paid at the discretion of the Chief Commissioner of Police, for information leading to the apprehension and subsequent conviction of the person or persons responsible for Tangey’s death.

The Director of Public Prosecutions will consider, according to official guidelines, the granting of indemnification from prosecution to any person who provides information as to the identity of the principal offender or offenders in this matter.