PHOENIX (AP) — A scathing U.S. Justice Department report released Thursday found that Sheriff Joe Arpaio’s office carried out a blatant pattern of discrimination against Latinos and held a “systematic disregard” for the Constitution amid a series of immigration crackdowns that have turned the lawman into a prominent national political figure.

Arpaio struck a defiant tone in response to the report, calling it a politically motivated attack by the Obama administration that will make Arizona unsafe by keeping illegal immigrants on the street. “Don’t come here and use me as the whipping boy for a national and international problem,” he said at a news conference.

The government found that Arpaio’s office committed a wide range of civil rights violations against Latinos, including unjust immigration patrols and jail policies that deprive prisoners of basic Constitutional rights.

The Justice Department’s expert on measuring racial profiling found the sheriff’s office to be the most egregious case of profiling in the nation that he has seen or reviewed in professional literature, said Thomas Perez, who heads the Justice Department’s civil rights division.

“We found discriminatory policing that was deeply rooted in the culture of the department, a culture that breeds a systematic disregard for basic constitutional protections,” Perez said.

The report will be used by the Justice Department to seek major changes at Arpaio’s office, such as new policies against discrimination and improvements of staff and officers. Arpaio faces a Jan. 4 deadline for saying whether he wants to work out an agreement to make the changes. If not, the federal government will sue him, possibly putting in jeopardy millions of dollars in federal funding for Maricopa County.

The fallout from the report was swift. The U.S. Department of Homeland Security announced it is severing its ties with Arpaio, stripping his jail officers of their federal power to check whether inmates in county jails are in the county illegally, a move that was meant to speed up deportation.

Homeland security officials also are restricting Arpaio’s office from using a program that uses fingerprints collected in local jails to identify illegal immigrants.

Arpaio has long denied the racial profiling allegations, saying people are stopped if deputies have probable cause to believe they have committed crimes and that deputies later find many of them are illegal immigrants. He called the report “a sad day for America as a whole.”

“We are going to cooperate the best we can. And if they are not happy, I guess they can carry out their threat and go to federal court,” Arpaio said.

Arpaio said the decision by Homeland Security to sever ties will result in illegal immigrants being released from jail and large numbers. They will go undetected and be “dumped on a street near you. For that, you can thank the federal government,” the sheriff said.

The Justice Department’s conclusions in the civil probe mark the federal government’s harshest rebuke of a national political fixture who has risen to prominence for his immigration crackdowns and became coveted endorsement among candidates in the GOP presidential field. Arpaio ultimately decided to endorse Texas Gov. Rick Perry, who denounced the findings Thursday as politically motivated.

Arpaio has built his reputation on jailing inmates in tents and dressing them in pink underwear, selling himself to voters as unceasingly tough on crime and pushing the bounds of how far local police can go to confront illegal immigration. He began aggressive sweeps in immigrant neighborhoods long before the state Legislature passed a 2010 law that cracks down on illegal immigrants and is now before the U.S. Supreme Court.

While widely popular among conservatives nationwide, Arpaio faces numerous problems at home that have him facing almost-daily calls to step down.

Apart from the civil rights probe, a federal grand jury also has been investigating Arpaio’s office on criminal abuse-of-power allegations since at least December 2009 and is specifically examining the investigative work of the sheriff’s anti-public corruption squad. The squad launched investigations of officials, lawyers and judges who ran afoul of Arpaio, and the cases all collapsed.

Arpaio has also been under pressure from his opponents to resign in the last week after an Associated Press article brought new attention to his office’s bungling of sex crime and molestation cases in a predominantly Hispanic Phoenix suburb. His office said more than 400 sex-crimes investigations had to be reopened after the department learned of cases that hadn’t been investigated adequately or weren’t examined at all.

Officials discovered at least 32 reported child molestations — with victims as young as 2 years old — where the sheriff’s office failed to follow through, even though suspects were known in all but six cases. The cases were originally reported by The Arizona Republic and other local media and received national attention in the last week.

Thursday’s report said federal authorities will continue to investigate whether the sex crimes are being properly looked at; complaints of deputies using excessive force against Latinos; and whether the sheriff’s office failed to provide adequate police services in Hispanic communities.

The report took the sheriff’s office to task for launching immigration patrols, known as “sweeps,” based on complaints that Latinos were merely gathering near a business without committing crimes.

Federal authorities single out Arpaio himself and said his office has no clear policies to guard against the violations, even after he changed some of his top aides earlier this year.

The report also said he and some top staffers tried to silence people who have spoken out against the sheriff’s office by arresting people without cause, filing meritless lawsuits against opponents and starting investigations of critics.

One example cited by the Justice Department is former top Arpaio aide David Hendershott, who filed bar complaints against attorneys critical of the agency along with bringing judicial complaints against judges who were at odds with the sheriff. All complaints were dismissed.

The anti-corruption squad’s cases against two county officials and a judge collapsed in court before going to trial and have been criticized by politicians at odds with the sheriff as trumped-up. Arpaio has defended the investigations as a valid attempt at rooting out corruption in county government.

The civil rights report said Latinos are four to nine times more likely to be stopped in traffic stops in Maricopa County than non-Latinos and that the agency’s immigration policies treat Latinos as if they are all in the country illegally. Deputies on the immigrant-smuggling squad stop and arrest Latino drivers without good cause, the investigation found.

A review done as part of the investigation found that 20 percent of traffic reports handled by Arpaio’s immigrant-smuggling squad from March 2006 to March 2009 were stops — almost all involving Latino drivers — that were done without reasonable suspicion. The squad’s stops rarely led to smuggling arrests.

Deputies are encouraged to make high-volume traffic stops in targeted locations. Latinos who were in the U.S. legally were arrested or detained without cause during the sweeps, according to the report.

During the sweeps, deputies flood an area of a city — in some cases, heavily Latino areas — over several days to seek out traffic violators and arrest other offenders. Illegal immigrants accounted for 57 percent of the 1,500 people arrested in the 20 sweeps conducted by his office since January 2008, according to figures provided by Arpaio’s office.

Police supervisors, including at least one smuggling-squad supervisor, often used county accounts to send emails that demeaned Latinos to fellow sheriff’s managers, deputies and volunteers in his posse. One such email had a photo of a mock driver’s license for a fictional state called “Mexifornia.”

The report said that the sheriff’s office launched an immigration operation two weeks after the sheriff received a letter in August 2009 about a person’s dismay over employees of a McDonald’s in the Phoenix suburb of Sun City who didn’t speak English. The tip laid out no criminal allegations. The sheriff wrote back to thank the writer “for the info,” said he would look into it and forwarded it to a top aide with a note of “for our operation.”

Federal investigators focused heavily on the language barriers in Arpaio’s jails.

Latino inmates with limited English skills were punished for failing to understand commands in English by being put in solitary confinement for up to 23 hours a day or keeping prisoners locked down in their jail pods for as long as 72 hours without a trip to the canteen area or making nonlegal phone calls.

The report said some jail officers used racial slurs for Latinos when talking among themselves and speaking to inmates.

Detention officers refused to accept forms requesting basic daily services and reporting mistreatment when the documents were completed in Spanish and pressured Latinos with limited English skills to sign forms that implicate their legal rights without language assistance.

The Justice Department said it hadn’t yet established a pattern of alleged wrongdoing by the sheriff’s office in the three areas where they will continue to investigation: complaints of excessive force against Latinos, botched sex-crimes cases and immigration efforts that have hurt the agency’s trust with the Hispanic community.