JERUSALEM — Nine people have been arrested in connection with a suspected price-fixing scheme for high school trips to former Nazi camps in Poland, the Israeli police said Tuesday.

The authorities raided tour company offices and confiscated equipment and receipts, a police spokesman, Micky Rosenfeld, said.

According to reports in Haaretz and by other Israeli news organizations, schools that send students on the tours are supposed to be able to choose the best prices from among several companies offering tours of former concentration camps and other sites in Poland that have connections to the Holocaust. The companies are on a list provided by the Education Ministry, and parents were charged about $1,500 for an eight-day tour.

But an inquiry led investigators to suspect that the tour operators had conspired to remove competition by fixing prices and dividing up the business from the schools. That would be a violation of Israeli antitrust law, Haaretz reported.