A series of offensive emails shared among Victoria Police officers are too shocking to ever be released publicly, the state's police chief says.
Up to 100 officers are being investigated and could face the sack for sending the emails on work computers.
The emails are extremely racist, homophobic and pornographic, officers have told media outlets.
The most serious email shows an ethnic man being tortured, The Age reported.
"We're not talking about one item, we're talking about multiple items," Police Chief Commissioner Simon Overland told ABC Radio.
He would not confirm the subject matter of the emails but said some were "extremely serious, some are offensive".
He also refused to confirm if the emails contained racist comments against Indian students or Africans - two minority groups who have criticised police conduct in recent months.
African youths have been targeted, bashed and abused by police, a recent report said.
"I'm not going to describe exactly the nature of the material in question," Mr Overland said on Thursday.
"If the Victorian public were aware of the nature of that material, I believe that it's of such a nature that it would cause significant concern within the Victorian community."
Mr Overland said some of the emails are so serious that they raise "real questions about a number of individuals' suitability to continue with Victoria Police."
The police ethical standards department has been using computer experts to track the email. The state's top police watchdog, the Office of Police Integrity, confirmed last week that it had also launched an investigation into racism in the force.
Two officers have already been given a "Section 68" over the email scandal, whereby Mr Overland notifies the officers that he has lost confidence in them and they must show cause why they should not be dismissed.
One of those officers, Sergeant Tony Vangorp, resigned from Healesville police station before he took his life.
"A tragic event has happened," Mr Overland said.
"No one wants to see this sort of thing happen. It's deeply, deeply regrettable and we need to learn the lessons but it doesn't mean that I can or should avoid my responsibilities around the good order and governance of Victoria Police."
Mr Overland admitted last week that a small minority of officers were racist, as he responded to a report that said police suffered from a culture of racism. "Racist attitudes held by members of Victoria Police - that is not okay.
Acting on those racial attitudes is clearly not okay and where we find it people can expect that I will deal with them in the strongest possible terms," he said.
