That message is a nightmare for Florence. The American consul general, Benjamin V. Wohlauer, who has met with the mayor and other leaders, noted in a statement that among other benefits, Florentine officials highly valued the “economic” contribution of American citizens. The city’s authorities have emphasized that they see this as an isolated, and freak, incident; that justice will be meted out quickly and harshly; and that Florence, a mecca for study-abroad students, remains safe.

“Our fear is that from today, a foreign student who sees an officer in uniform might be worried,” said Mayor Dario Nardella in an interview, adding that he was working with the American Consulate, scores of American universities and law enforcement agencies to make sure students had faith in the city’s uniformed police officers after an “unjustifiable” breach. “We have to regain their trust,” Mayor Nardella said.

The mayor is desperate to avoid the sensationalism that inundated Perugia a decade ago during the long trial of Amanda Knox, an American college student accused, and ultimately exonerated, of murder. He said he had urged the Carabinieri commander to hire more women and instructed city lawyers to file a civil suit against the officers, whom he called “disgusting,” primarily to ensure that the case moves as quickly as possible through the byzantine Italian judicial system.

The provincial commander of the Carabinieri, Giuseppe De Liso, said in an interview that when he heard the news, he called the American consul right away. Disciplinary action was immediately taken against the two officers, he said, which could eventually result in their expulsion, an outcome the Italian Defense Minister, Roberta Pinotti, who oversees the Carabinieri, has all but said is a certainty.

In his headquarters, a former convent, decorated with antique illustrations of Carabinieri uniforms throughout the centuries, Mr. De Liso said he needed to eradicate any suspicion of a cover-up and to restore the honor of his beloved police force.

“We can’t let those two officers smear 200 years of history,” he said.

Taken together, the accounts of local law-enforcement authorities, officials, lawyers for the Carabinieri officers and the women make for what many Italians have called an almost unimaginable scandal.

The two women arrived in Florence at the end of August for a semester abroad from their university in New Jersey. On Sept. 6, they began drinking wine and limoncello at a popular piazza, or public square, where Italians sip on the steps of a church and Americans tend to guzzle in the bars.