The Oakland Police Department is investigating three current officers accused of sexual misconduct with a woman who may have been underage at the time.
Oakland Mayor Libby Schaaf said the allegations are "very disturbing" and could hurt efforts to build trust with the public.
Speaking at a late afternoon news conference at City Hall, where she was joined by Police Chief Sean Whent, Schaaf said, "This type of misconduct doesn't do justice to the citizens of Oakland and does an injustice to a (police) department that has made tremendous progress" in making reforms to comply with the 2003 settlement of a major misconduct lawsuit.
Schaaf said, "It's truly tragic that this conduct is happening at this time. Although there's still more work to do, the department has worked hard to develop the public's trust."
Whent said the three officers have been placed on paid administrative leave while the department investigates the allegations.
The Oakland Police Department has also been rocked by the recent public disclosure that 30-year-old Officer Brendan O'Brien committed suicide last Sept. 25 and that his wife, Irma Huerta-Lopez, committed suicide on June 16, 2014.
A source told NBC Bay Area the sexual misconduct case came to light last September when O'Brien committed suicide. Sources said O'Brien left a note that implicated the officers involved in the sexual misconduct investigation.
Whent said he was "very concerned" about Huerta-Lopez's death and ordered "a very thorough investigation" that included senior homicide investigators to determine if it was a suicide or a homicide.
But he said the investigation concluded that her death was a suicide, even though there were two gunshot holes at the couple's apartment in the 8000 block of Greenridge Drive in the Oakland hills.
Whent said it's "not uncommon" for people who commit suicide to fire two shots and gunshot residue was found on Huerta-Lopez's hands.
Residue was also found on O'Brien's hands, but police said that may have been a result handling weapons as part of his duties as an officer.
Schaaf said that as of Friday the Alameda County District Attorney's Office has agreed to conduct parallel and independent investigations of the sexual misconduct allegations as well as of the apparent suicides of O'Brien and Huerta-Lopez.
She said that to make sure that the District Attorney's investigations are unbiased, no former Oakland police officers who work as investigators for the District Attorney will be involved in the probes.
Schaaf said she also issued an executive order requiring that the District Attorney's Office be notified of any future suspicions of wrongdoing on the part of Oakland officers.
Whent said the sexual misconduct allegations against the three officers "are extremely troubling" and he has asked his department's inspector general to look at all alleged officer misconduct incidents in the past several years.
Whent said many of the incidents involved conduct by officers when they were off duty but he expects his officers to maintain high standards both on and off duty.
Whent said the "overwhelming majority" of his officers are honest and hard-working but he said the recent misconduct allegations "have marred our reputation."