OAKLAND — Two of the four Oakland police officers placed on paid leave in a sexual misconduct investigation have resigned, the department said Wednesday.

Oakland police spokeswoman Officer Johnna Watson declined to name the officers, citing the ongoing investigation. On Monday, officials said a fourth officer had been placed on leave in a growing scandal first uncovered after another officer committed suicide in September.

“The Oakland Police Department can confirm that two of the four officers who were placed on administrative leave as part of our ongoing investigation into a recent misconduct case have resigned,” according to a department statement. “The Internal Affairs Division will continue to investigate all of the misconduct allegations.”

Officer Brendan O’Brien, who committed suicide by gun on Sept. 25, left a note naming specific officers who allegedly were involved with a police dispatcher’s daughter who goes by the name Celeste Guap, according to a source who read the note.

Oakland police initially investigated but did not take any action. However, since then, the independent monitor overseeing department reforms learned of the allegations and raised questions.

Last week, Mayor Libby Schaaf said the Alameda County District Attorney’s Office was going to conduct an independent review of the sex allegations, and deaths of O’Brien and his wife, Irma Huerta Lopez, who committed suicide a year earlier.

Huerta Lopez’s death was briefly investigated as suspicious but later ruled a suicide. Her sister, Paulina Huerta, told this newspaper she still has doubts about Huerta Lopez’s suicide and has blamed O’Brien.

“The Oakland Police Department is committed to transparency,” the statement read. “However, a complete investigative process requires confidentiality in order to maintain the integrity of the investigation. For this reason, only those preliminary details that do not compromise the investigation can be released at this time.”

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David DeBolt covers Oakland. Contact him at 510-208-6453. Follow him at Twitter.com/daviddebolt.