Thirty-five Merseyside Police officers and staff are being investigated after offensive e-mails were allegedly found on their work computers.
Police officers who store offensive e-mails risk being sacked
E-mails about black and gay people and women - the exact content of which has not been revealed - were detected by the force's computer monitoring system.
Those under investigation risk disciplinary action or possibly losing their jobs.
The force has announced tough measures for those who breach the rules.
"These e-mails are offensive either in terms of their racist, homophobic or sexual content and we will not allow them to infiltrate into offices or stations," said Grahame Barker, assistant chief constable of Merseyside Police.
He went on to say that most people who had received those e-mails had deleted them straight away, while others had kept and, in some cases, forwarded them.
"Just to be in possession of an e-mail of this type is a serious breach of our standards and to forward them is absolutely unacceptable," Mr Barker added.
He said the outcome of the investigation was difficult to anticipate, but added that "stringent measures" would be enforced to monitor email.
He added that all 6,200 staff would be reminded they had a responsibility to communicate "with integrity and responsibility".
Inspector Irene Afful, chairperson of Merseyside Black Police Association, said: "Literature of this nature is offensive and has no place in a professional organisation such as Merseyside Police."
The force has warned staff they face disciplinary action if found in possession of offensive e-mail.
The e-mail system will be "cleaned" to remove any trace of the messages.