Passage: Until 2009, the Swedish Ombudsman against Discrimination on Grounds of Sexual Orientation (Ombudsmannen mot diskriminering på grund av sexuell läggning), normally referred to as HomO, was the Swedish office of the ombudsman against discrimination on grounds of sexual orientation. The Ombudsman against Discrimination on Grounds of Sexual Orientation ceased to exist on 1 January 2009; it was merged with the other Ombudsmen against discrimination into a new body: the Discrimination Ombudsman. The previously existing acts against discrimination were also replaced with a new discrimination act.The term HomO was used both to refer to the office and the title of its government-appointed acting head; the last HomO was Hans Ytterberg. The HomO investigated grievances of individuals and files class action suits on their behalf, for example a successful action against a restaurant owner in Stockholm who had harassed a lesbian couple. The HomO office was key in taking a number of initiatives of its own and submitting parliamentary proposals, such as the legalisation of same-sex marriage.

Question: Who investigated complaints and files the lawsuits?
The HomO