After a week of denying any knowledge of the family's whereabouts, the police say the three women were arrested for forgery and tax evasion.
Though, last week, Rwanda Police spokesman, Theos Badege told the BBC that they did not know the whereabouts of Diane, her mother and sister.
"They are said to be where they want to be, and because ours was just to conduct the search, which is part of the investigation... we don't know where they are," he said.
On September 4, Rwanda police tweeted the following:
The 35-year-old politician and her family have returned home. However, police they could be called back by for further questioning.
Rwigara and her family have denied the allegations against them.