Park Won-soon, 64, died in an apparent suicide last week shortly after the sexual harassment claims were filed with police, meaning that the victim's claims won't be criminally investigated.

But the accusations of Park's former secretary have sparked a firestorm among women's rights groups in South Korea, and raised questions over how seriously sexual harassment is really taken by President Moon Jae-in, who campaigned on the promise of becoming a "feminist president."

Park is now the third top leader associated with Moon's Democratic Party to be accused of sexual harassment or assault in recent years. As the Seoul City Government launches an internal investigation into Park's alleged misconduct, there are calls for both the party -- and the government -- to do more to support victims of sex crimes.

Four years of alleged harassment

Like Moon, Park described himself as a feminist.

As Seoul's mayor -- a role that made him the second-most powerful official in South Korea -- he implemented welfare policies aimed at helping women and was a vocal supporter of the #MeToo movement. A former human rights lawyer, in the 1990s Park represented the victim in one of South Korea's first successful sexual harassment convictions. In the 1980s, he was part of the team of lawyers who represented one of the first women to bring charges of sexual assault against authorities.

So for many in Seoul, last week's allegations came as a shock.

In a press conference Monday, the alleged victim's lawyer, Kim Jae-ryon, claimed Park had sent pictures of himself in his underwear to his secretary, as well as obscene, late-night messages over the encrypted app Telegram. On one occasion, when he saw a bruise on her knee, he pretended to blow air on it to ease the pain but allegedly touched her knee with his lips, Kim said.

The four years of alleged harassment began when the woman was hired as Park's secretary and continued after she had moved to another department, said Kim. In a letter written by the accuser, and read at Monday's press conference, the alleged victim said she "should have screamed the first time it happened" and she regrets not coming forward earlier.

CNN has reached out to the accuser through her lawyer. The lawyer did not wish to comment beyond what she said at the press conference. Park did not comment on the allegations before his death.

Attempts to speak out

Park's former secretary did try to speak up earlier, but was discouraged, women's rights groups said.

The former secretary claims she asked people at the Seoul City Government for help, but her complaints were brushed off as the mayor making simple mistakes. She was also told that her duty as secretary was to help the mayor emotionally, so she felt as if she couldn't speak out, according to conversations between the woman and non-profit Korea Sexual Violence Relief Center. CNN reached out to the Seoul City Government for comment.

Even after the woman told police, women's rights groups alleg