Officials agreed Wednesday to pay $3.5 million to settle a lawsuit that alleged metro Phoenix's sheriff botched the investigation into the rape of a 13-year-old girl and failed to arrest the suspect who then went on to sexually attack her again.

The girl's rape case was among more than 400 sex-crime cases that were inadequately investigated or not looked into at all by Maricopa County Sheriff Joe Arpaio's office over a three-year period ending in 2007.

The decision to resolve the lawsuit by the girl's guardians marks the latest in a long string of legal settlements against Arpaio's office. The county had previously paid more than $68 million in judgments and settlements against the sheriff's office during Arpaio's ongoing 22-year tenure. Some settlements resolved lawsuits filed over the treatment of inmates in Arpaio's jails and the sheriff's failed corruption investigations of political foes.

The settlement Wednesday applies only to the lawsuit over the 13-year-old girl, who eventually got an abortion after she became pregnant from a subsequent attack. It's unknown whether other victims in the botched investigations have filed similar lawsuits.

Arpaio, through a spokeswoman, declined an interview request. Spokeswoman Lisa Allen said the police agency agrees with the decision by county officials to resolve the lawsuit. "Today, this matter concludes and our hope is that the money awarded will go to a trust fund providing this victim with the help she requires now and in the future," Allen said in a statement.

The botched sex-crimes investigations served as an embarrassment for Arpaio, who promotes himself as "America's Toughest Sheriff" and eventually reopened the more than 400 of its sex-crime cases. The sheriff apologized in December 2011 for the bungled cases, and his office has since said it has moved to clear up the cases and taken steps to prevent the problem from happening again.

An internal review attributed the failures to understaffing and mismanagement. A former supervisor says her investigators were pulled away from time to time to help with training efforts and Arpaio's immigrant-smuggling squad.

The lawsuit by the 13-year-old girl's guardians alleged that the subsequent attacks on the girl could have been avoided if Arpaio's office arrested the suspect after he first abused her in March 2007 and threatened to kill her if she reported the allegations.

The sheriff's office responded to the initial rape allegation after it was revealed to officials at her school a day after the attack. A sheriff's deputy interviewed the girl, who underwent a forensic exam to seek evidence of rape, the lawsuit said.

The lawsuit said crime lab officials told the sheriff's office less than two weeks after the attack that it needed a blood sample from the suspect, whose identity was known to investigators.

Instead, the lawsuit alleged the sheriff's office did nothing to push the investigation forward for more than three years. During that time, the suspect continued his sexual attacks on the girl, leading to her pregnancy, which was aborted in 2009, the lawsuit said.

The girl's case was reopened in June 2011, leading to the suspect's arrest. In the end, he pleaded guilty to one count of child molestation and two counts of attempted child molestation and was sentenced to 24 years in prison.

The Associated Press