Judge hears challenge to 2004 NY police mass arrests

NEW YORK (Reuters) - New York City police did not have probable cause to justify mass arrests of protesters during the 2004 Republican National Convention, lawyers for some of those detained told a U.S. judge on Thursday.

In a crowded courtroom in U.S. District Court in Manhattan, Judge Richard Sullivan heard oral arguments over cases that were filed over seven years ago and raised questions about police tactics well before the Occupy Wall Street movement.

More than 1,800 demonstrators were arrested over an eight-day period in August and September 2004 as the Republican Party met in New York to nominate George W. Bush as its candidate in the presidential election. Demonstrators marched in the streets to protest Bush's policies including the Iraq war.

The court hearing on Thursday centered on dozens of cases stemming from the mass arrests of almost 600 people at two locations in Manhattan. Almost all of those arrested filed lawsuits accusing the New York Police Department of indiscriminately and unlawfully detaining them.

"There is no way a reasonable officer could have concluded that everyone walking on that sidewalk had violated the law," New York Civil Liberties Union lawyer Christopher Dunn said.

The plaintiffs contest the so-called "group probable cause" theory advanced by New York City which holds that if a police officer believes that a group of people appears to be breaking the law in unison, they are authorized to arrest the group.

"The police made reasonable efforts to believe that the people who were placed under arrest had engaged in unlawful conduct," said New York City lawyer Peter Farrell.

The judge did not immediately rule on the motions by the plaintiffs and the City.

(Reporting by Basil Katz; Editing by Cynthia Osterman)