A Davis Wright Tremaine partner has resigned from the firm after reports that the humanitarian organization on whose board he served, Mercy Corps, failed to adequately address serious sexual abuse allegations against its founder.

In an internal firm email sent Friday, Davis Wright Tremaine’s managing partner, Jeffrey Gray, said Robert Newell, a litigation partner in the Seattle-based firm’s Portland office, had resigned, effective immediately. Until last week, Newell was a board member for Mercy Corps, a major international nonprofit and a pro bono client of the law firm. The Oregonian reported earlier this month that the charity for decades covered up allegations that founder Ellsworth Culver, who died in 2005, sexually abused his daughter, Tania Culver Humphrey.