A new study finds that hundreds of police officers are arrested each year for the same sorts of crimes they are supposed to be thwarting.

The study, believed to be the first of its kind, was conducted by researchers at Bowling Green State University and funded by the National Institute of Justice, which released the report this month. Researchers identified 6,724 cases involving the arrests of 5,545 sworn officers across the nation between 2005 and 2011.

That means that on average, police officers are getting arrested around 1,000 times per year.

Alarmingly, forty-one percent of the total crimes were committed while on duty. Philip Stinson, lead researcher on the study and BGSU professor, told The Huffington Post that even when off-duty, some of these officers committed crimes using powers endowed to them as sworn members of law enforcement or knowledge gained through their authority as police officers -- thereby making the distinction murky in some cases.

"Police officers can’t seem to turn it off at night," Stinson said.

The alleged crimes cops were arrested for most frequently were simple assault, driving under the influence and aggravated assault. Altogether, those crimes made up one-third of the total cases. There were also a considerable number of sex crimes cases, including forcible fondling and forcible rape -- about 10 percent of all cases -- and, disturbingly, the sex crimes cases included some victims under the age of 18. While the victims were mostly female, there were some male victims as well, Stinson said Thursday during a web conference detailing the report.

"Our first and perhaps most salient general observation about the data was that police crimes are not uncommon and that they occur with some regularity in jurisdictions across the nation," the report reads. "The sheer number of police crimes directly contradicts the presumption that they are perpetrated by a small cadre of problem-prone officers."

Stinson and his co-authors broke the cases of arrest into five broad categories:

sex-related police crime (1,475 arrest cases of 1,070 sworn officers)

alcohol-related police crime (1,405 arrest cases of 1,283 sworn officers)

drug-related police crime (739 arrest cases of 665 sworn officers)

violence-related police crime (3,328 arrest cases of 2,586 sworn officers

profit-motivated police crime (1,592 cases of 1,396 officers)

Male police were arrested at a far higher rate than female officers: Almost 95 percent of police crimes were committed by males.

About 72 percent of arrest cases resulted in convictions, Stinson said. Still, only about half of the total cases ultimately resulted in job loss for the arrested officers. The reasons for that are complex, the researchers noted, but in part, professional discipline may be lacking following an officer's arrest because their own department may not know about the crime committed. That's because about two-thirds of all the cases originated from arrests made by a police department that didn't employ the officer arrested, meaning, in at least some cases, police departments may not be aware that some of their own officers are committing crimes.

Stinson and his colleagues say there are several things that law enforcement agencies can do to help keep cops from breaking the law. For example, they could perform annual criminal background checks for their sworn officers, and have written policies in place that specify standards for responding to police officers being arrested. They also could adopt policies compelling mandatory disclosure whenever an officer is arrested for a crime or when the agency issues an order of protection against the officer.

Because the researches also found instances of mental illness in some of the cases, as well as officers experiencing an "unraveling of their lives" following their arrest, they say agencies should install early warning systems to track officer arrests. That way, the officers can be referred to employee assistance programs when appropriate.

The full number of police officer crimes is likely higher than what the BGSU researchers found. The researchers used media reports to determine when an officer was arrested, so any crimes committed by an officer not reported by a law enforcement agency or discovered by a news organization are not included in the data.

"We know that, as a general matter, crime is underreported," David Harris, a professor of law at University of Pittsburgh School of Law who studies policing, told HuffPost. "Some types are underreported much more than others. There is no reason to think this would not be true with crimes by police."

Harris also noted there is evidence that police officers are reluctant to report misconduct by fellow officers and that some agencies tend not to take seriously any complaints of misconduct, criminal or otherwise. Those factors may also contribute to a lower rate.

Given the limitations of the data available, Jonathan Blanks, a researcher with Cato’s National Police Misconduct Reporting Project, said the absolute number of crimes committed by police is likely "unknowable." He outlined some of the reasons why on Thursday in a blog post about the new report:

We find cases where officers are arrested and convicted of crimes. But we also find officers who are given “professional courtesy” and not arrested for drunk driving. We see cases in which officers plea down their violent and disturbing felony cases to misdemeanor disorderly conduct, which allows them to maintain their peace officers’ license. We find longstanding criminal conspiracies that sometimes take years to uncover. And, just today in Baltimore, we see prosecutors unable to convict the officer believed to be most culpable for the conduct that resulted in the death of Freddie Gray. It is impossible to gauge the extent of misconduct because we don’t know how much of it the police and the media are catching.

There are are roughly 750,000 sworn local and state law enforcement officers in the U.S., according to a recent count by the Department of Justice, and Stinson's data estimates the rate of arrest for officers during the years of his study is 1.7 cops per 100,000 people. As a comparison, the approximate rate of arrest of civilians in the U.S. is around 3,888 per 100,000 people, according to FBI Uniform Crime Report data. The vast difference in those rates may lead some to diminish the importance of the report's findings. But Stinson says comparing the two rates is missing the larger point of the research: Government agents whose duty it is to uphold the law should not be breaking the law.

"Police officers should not be getting arrested," Stinson said. "Yes, the rates of arrest are very low. But, this stuff is nuts. And the fact that officers are arrested for so many different types of crimes is simply amazing to me."

Stinson argues the data points toward a set of issues related to "the process of police socialization and the deep police subculture" that demand further scrutiny.

"They just do whatever they want to do," Stinson says, "because law enforcement is exempt from law enforcement."