It seemed yet another in a string of what have euphemistically come to be called, in the US, ¡°officer-involved shootings¡±: the killing, in the Midwestern city of Cincinnati in July, of a black motorist by a white policeman.

But this incident, captured on video, was different. The officer, who was eventually charged with murder, worked for the University of Cincinnati.

It was the latest in an escalating number of such incidents involving university police that is exposing the growth of the armed and well-equipped departments, many of which have the same powers as municipal police and can operate beyond the boundaries of their campuses. It has also highlighted how complex their jobs have become in an era of campus shootings, sexual assaults, conflicts with surrounding neighbourhoods and scrutiny of their behaviour.

¡°You have setbacks with incidents like that,¡±?Bill Taylor, police chief at San Jacinto College near Houston and president of the International Association of Campus Law Enforcement Administrators, said about the Cincinnati incident. ¡°That is problematic when we¡¯re looked at in the same way as the rest of law enforcement.¡±

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And Cincinnati was not the only headline-grabbing incident involving US university police over the past year.

Florida Atlantic University reached a confidential settlement in a lawsuit brought by the family of a woman killed by a campus police officer who had been fired by a nearby sheriff¡¯s office and rejected by 11 other police departments before being hired by the university.

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Brown University officials had to apologise after a campus police officer handcuffed a visitor who was attending a meeting of Ivy League Hispanic student leaders.

And the police chief at Abraham Baldwin Agricultural College was fired after saying that reports of sexual assaults often result from ¡°women waking up the next morning with a guilt complex¡±.

As critics push for reforms in municipal police departments, ¡°campus police are often overlooked, yet a lot of the issues¡­that have been an issue with local law enforcement you¡¯re seeing now with campus police¡±, said Denise Rodriguez King, a research analyst with non-profit organisation CNA, which provides training and technical assistance to police and policymakers.

The stakes have also grown higher. Violence on campus in the US has become almost commonplace in the years since 32 people were fatally shot by a gunman at Virginia Tech in 2007. Nine people were killed in October at an Oregon community college. A few days later, one person was killed and three wounded at an Arizona university, and four were stabbed at the University of California, Merced.

Many universities have expanded and armed their police departments; one major Catholic institution, Villanova University, has announced that it will establish a police force for the first time next year. Seventy-five per cent of campuses now have armed officers, according to the US Bureau of Justice Statistics, and campus police at 92 per cent of public institutions have been given the right by surrounding law-enforcement agencies to operate outside their campuses.

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One of three people killed by a gunman at a Planned Parenthood women¡¯s reproductive services clinic in Colorado this weekend was a campus police officer,?Garrett Swasey of the University of Colorado at Colorado Springs, who was among the first to respond to the off-campus incident. And the Cincinnati shooting occurred half a mile from the campus, although the city has since suspended an agreement that allows university police officers to make traffic stops off-campus.

University police also have an image problem, said John Venuti, chief of police at Virginia Commonwealth University.

¡°There is a little bit of a perception where campus law enforcement is considered to some degree lesser than regular law enforcement,¡± he said. ¡°But the things we¡¯re doing, most police departments in the US will be doing the exact same things.¡±

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That also means that university police have increasingly used deadly or near-deadly force. The Merced attacker was shot and killed by university police. In November, a white police officer at Spartanburg Methodist College shot and killed a black student who, he said, had tried to run him over. Last year, a San Jose State University police officer shot and killed a man who was holding a 12-inch saw.

Some states, including Texas, have responded to campus shootings by allowing students and others to carry guns, despite opposition from the American Association of University Professors, the? Association of American Colleges and other groups.

But that¡¯s yet another headache for campus police.

¡°If we have a situation on campus where my people are responding to an active shooter situation, we don¡¯t have a way to distinguish a person who has a concealed handgun licence from someone who¡¯s an active shooter,¡± Mr Taylor said. ¡°There¡¯s nothing to differentiate the good guys from the bad guys.¡±

Meanwhile, growing discord over racial sensitivity on campus and broader criticism of police tactics nationwide mean that university police are also under closer scrutiny from constituencies that are not shy about expressing disapproval.

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¡°We¡¯re dealing with a clientele that expects more out of us,¡± said Mr Taylor.