Police Scotland's counter corruption unit is being investigated amid a criminal allegation officers attempted to pervert the course of justice.
In a letter to the Scottish Parliament's justice committee, Chief Constable Phil Gormley said there were a further 11 non-criminal allegations all made by a member of the force earlier this year.
Mr Gormley said there had been a total of 25 complaints involving 108 allegations made against counter corruption officers since 2009, many of which pre-dated the creation of Police Scotland in 2013. Most of the files have now been closed.
Mr Gormley said: "I would like to take this opportunity to inform the committee that a further complaint made by a member of Police Scotland about the counter corruption unit within the above time period has been identified.
"The complaint includes one criminal allegation of an attempt to pervert the course of justice and 11 non-criminal allegations. This is currently the subject of an investigation."
The chief constable also confirmed a murder inquiry into the death of sex worker Emma Caldwell was not "live" when a senior officer told MSPs it was.
Deputy Chief Constable Neil Richardson, who has since retired from the force, has been accused of misleading the Scottish Parliament's justice committee over the matter.
Durham Constabulary is currently carrying out a review of complaints against staff in the counter corruption unit at Police Scotland's request.