Five police officers from four different forces are facing disciplinary action over messages about Wayne Couzens.
Now, two officers from the Metropolitan Police, and one from each force in Sussex, Dorset and Avon and Somerset are subject to misconduct hearings.
One of the Met Police officers facing disciplinary action was referred to the Independent Office for Police Conduct (IOPC) in March.
The constable on probation, who went on to staff a cordon as part of the search for Ms Everard, was investigated over allegations they used WhatsApp "to share with colleagues an inappropriate graphic, depicting violence against women" while off-duty.
The investigation, completed in August, indicated that the graphic was intended to be in reference to the kidnap and murder of Sarah Everard.
The IOPC said: "The image was highly offensive and the officer now has a case to answer for misconduct for potentially breaching standards of professional behaviour for conduct and authority, respect and courtesy. The officer will face a misconduct meeting to answer the allegations."
Another probationary constable had a case to answer for "allegedly sharing the graphic and failing to challenge it" and will also be subject to a misconduct meeting.
An officer from Dorset Police, who was on secondment from the force at the time of the alleged offence, is facing a gross misconduct hearing.
It is alleged that the officer posted details of an interview given by Couzens under caution, which were presented during a non-reportable court hearing.
In April this year, police watchdog, the Independent Office for Police Conduct (IOPC), warned officers about the "unacceptable use of social media".
The warning was based "on a number of cases involving the posting of offensive and inappropriate material", the IOPC regional director, Sal Naseem, said.
He added that the allegations if proven, have the "capacity to further undermine public confidence in policing".
"They also once more illustrate the potential consequences for officers and come at a time when policing standards and culture have never been more firmly in the spotlight," Mr Naseem added.
The IOPC wrote to the National Police Chiefs Council asking them to remind forces and officers of their obligations under the police Code of Ethics and Standards of Professional Behaviour."
Other ongoing investigations are looking at how Kent Police in 2015, and the Met in 2021, handled allegations of indecent exposure now linked to Couzens.
Both investigations are considering whether policies and procedures were followed, and if any issues identified may have impacted the vetting of the former officer.