A Rwandan accused of involvement in his country’s 1994 genocide has been arrested in Frankfurt, and German authorities are considering his extradition to Rwanda, a prosecutor said Wednesday.

Callixte Mbarushimana was arrested Monday at Frankfurt airport as he tried to board a plane for St. Petersburg, Russia, Frankfurt prosecutor Volkmar Kallenbach said.

Mbarushimana, a 44-year-old Rwandan Hutu, has been accused in Rwanda of genocide and crimes against humanity, Kallenbach said. He added that Mbarushimana disputes the charges.

Kallenbach said the process of deciding whether to extradite him to Rwanda could take up to eight weeks. Rwanda and Germany have no formal extradition agreement.

Several witnesses have said Mbarushimana killed at least two people and ordered the killing of about 30 more during the genocide, in which more than 500,000 Tutsis and moderate Hutus were massacred over three months.

A former U.N. employee, Mbarushimana continued to get jobs with the world body after the claims came to light in the mid-1990s.

In 2002 Carla Del Ponte, then Rwanda U.N. tribunal prosecutor, refused to sign a draft indictment against Mbarushimana, saying evidence was inadequate.

Mbarushimana has been living in France in recent years.