Mercy Corps confirmed Tuesday that a long-serving board member resigned as The Oregonian/OregonLive was preparing to publish an investigation that shows the world-renowned international relief agency mishandled sexual abuse allegations against one of its founders.

The Oregonian/OregonLive found that Mercy Corps executives knew co-founder Ellsworth Culver had been credibly accused by his daughter of serial sexual abuse in the early 1990s but allowed him to continue at Mercy Corps in a top role for more than a decade.

The $471-million-a-year charity twice rebuffed Culver’s daughter, Tania Culver Humphrey -- 25 years ago when she first detailed her allegations to Mercy Corps officials and again last year when she asked them to reexamine how they conducted the initial review. That initial review was undertaken by board member Robert Newell, co-founder Dan O’Neill and then-board chairman Raymond Vath.

Mercy Corps CEO Neal Keny-Guyer confirmed Tuesday that Newell had resigned from the board after Mercy Corps was informed of the news organization’s findings.

Newell, who Keny-Guyer once called “the heart and soul of Mercy Corps," served on the Mercy Corps board since its founding in 1981. He also serves as treasurer and is a partner at the Davis Wright Tremaine law firm in Portland.

Newell, 72, declined to answer questions about his interactions with Humphrey and his role in the review.

But in a written statement, Newell on Tuesday said the board took Humphrey’s allegations “very seriously when they were brought to our attention.” He called the investigation challenging and said it was unclear at the time why state child welfare authorities had not intervened.

“But nothing changes the fact that no one should endure what she has described, especially not as a child at the hands of her father,” Newell wrote. “It is as troubling to me now as it was back then.”

The Portland-based relief agency on Monday also scrubbed warm tributes to Culver from its website. It took down photos and tributes to Culver from the walls of its headquarters.

After his daughter’s original accusations, Culver remained a prominent figure within Mercy Corps and continued to serve as its public face, meeting with global leaders and spearheading efforts to expand into China until his death in 2005.

Humphrey, now 48, told The Oregonian/OregonLive her father sexually abused her from preschool into high school. She said she told Mercy Corps leaders that her father had masturbated on her, touched her inappropriately, kissed her in a sexualized manner and forced his penis into her mouth while showering with her.

After its initial review of Humphrey’s allegations, Mercy Corps determined there was insufficient evidence to support her allegations.

Last fall, after Humphrey’s husband contacted Mercy Corps and said his wife was suffering from the trauma of the abuse, the humanitarian organization eventually replied that it stood by its original assessment.

The news organization typically does not name victims of sexual abuse, but Humphrey requested that she be identified.

The Oregonian/OregonLive’s 10-month investigation into Humphrey’s allegations also identified eight friends from her childhood and teen years who confirmed that Humphrey told them about the abuse at the time. Three said they saw Culver grope or molest her in a car or during sleepovers. Two said they saw injuries on her legs and neck that Humphrey explained were from her father’s use of force or restraints during the assaults. One of her friends from St. Mary’s Academy in Portland came forward in the course of the investigation with her own account of sexual abuse by Culver.

On Tuesday, Keny-Guyer offered a forceful apology, taking full responsibility for Mercy Corps’ mishandling of Humphrey’s request last year to revisit her allegations and how she was treated. He called the news organization’s findings “deeply shocking and troubling.”

“I’m reeling,” Keny-Guyer said in an emotional interview in Mercy Corps’ Old Town offices. He said the findings “changed everything.”

“They are heartbreaking, they are horrifying,” he said. “My profound apology goes out to Tania and her family.”

This is a developing story.

-- Noelle Crombie

503-276-7184

ncrombie@oregonian.com

@noellecrombie

Visit subscription.oregonlive.com/newsletters to get Oregonian/OregonLive journalism delivered to your email inbox.