Prosecutors have ruled out bringing homicide charges over the death of a Victorian Station worker Belly Mujinga.
The 47-year-old died with coronavirus two weeks after reportedly being spat at by a passenger claiming to have the disease.
The Crown Prosecution Service's decision came after medical tests confirmed the suspect had not been infected with Covid-19.
Mrs Mujinga left behind her husband and 11-year-old daughter.
British Transport Police (BTP) interviewed a 57-year-old man over the incident.
However, they said there was not enough evidence a crime had taken place, following a review of statements from key witnesses, including colleagues, and CCTV footage.
Detectives found there was insufficient evidence of spitting or another action that could lead to infection and concluded Mrs Mujinga's death did not occur because of that incident.
But they asked the Crown Prosecution Service (CPS) to review the evidence and look into whether there were any further lines of inquiry, following a wave of public anger over Mrs Mujinga's death.
Deputy chief Crown prosecutor Suzanne Llewellyn said on Thursday: "Belly Mujinga's death from Covid-19 aged just 47 in April was a heartbreaking event that shocked the country.
"At the request of BTP, following their decision to take no further action in this case, the CPS has now independently reviewed the evidence and advised on any further lines of inquiry that might support a prosecution.
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"We considered whether charges could be brought in relation to homicide, assault or public order offences.
"As part of this review, we studied enhanced CCTV, forensic materials and witness statements.
"CCTV and witness evidence was insufficiently clear and consistent to substantiate allegations of deliberate coughing or spitting, meaning no charges can be brought for assault or public order offences.
"Medical tests confirmed the suspect had not been infected with coronavirus, which together with the lack of other evidence rules out any charges in relation to homicide.
"Therefore after careful consideration and with all lines of inquiry explored, we have advised BTP no further reliable evidence has become available to change their original decision in this case.
"We have met with the family of Ms Mujinga to explain our reasoning, which we know will be disappointing for them. Our deepest sympathies remain with the family."
