(07-16) 17:48 PDT ANTIOCH -- A group of African American, low-income tenants accused the city of Antioch in a lawsuit Wednesday of trying to drive them out of federally subsidized housing by creating a police squad to target blacks for arrests, harassment and pressure on their landlords to evict them.

As more black families have been drawn to affordable housing in the Contra Costa County community, "the city has reacted with alarm and hostility to the newcomers, choosing to scapegoat them as the cause of economic downturn," lawyers for five renters declared in papers filed in federal court in San Francisco.

At a news conference, tenants said police had entered and searched their homes without warrants or any evidence of crimes, had warned their landlords that they could be held responsible for tenants' misconduct, and had asked the county housing authority to eliminate the Section 8 subsidies that kept their rents affordable.

One plaintiff's landlord, Riaz Patras, said at the news conference that an Antioch police officer advised him last year not to rent to African Americans.

The suit alleges that the police Community Action Team, established in July 2006 to patrol high-crime neighborhoods, has violated state and federal laws and constitutional guarantees against racial discrimination and illegal searches. Antioch officials vehemently denied the allegations.

"Any objective review of our city's policing efforts will reveal that these efforts are focused exclusively on criminal and/or dangerous behavior," the city said in a statement.

The suit, an expansion of a case filed by four of the plaintiffs last month, seeks class-action status on behalf of about 800 African Americans with Section 8 housing subsidies in Antioch. It seeks damages for the individual plaintiffs and court orders against unfounded searches and harassment.

Lawyers for the plaintiffs said city leaders have reacted fearfully to the near-doubling of Antioch's African American population in the last five years. Black people now make up about 15 percent of the city's 101,000 residents.

The suit quoted City Council members as saying at meetings in 2006 and 2007 that they were determined to keep Antioch from becoming as violent as Richmond and blamed problems on an influx of Section 8 renters, most of whom are black. Plaintiffs' lawyer Brad Seligman said Police Chief James Hyde has encouraged residents at neighborhood meetings to file complaints against Section 8 residents.

Two-thirds of the Community Action Team investigations focus on African Americans, the plaintiffs' lawyers said, and black households are the targets of 70 percent of police complaints to the Housing Authority - which, the lawyers said, finds a majority of such complaints unfounded.

Police "invaded my home and terrorized my family," plaintiff Karen Coleman said at the news conference. "They told me my Section 8 benefits were going to be terminated."

The lawsuit alleged that four officers came to Coleman's door in June 2007, saying they were looking for her husband, a parolee, and entered over her objections. They searched the home, took pictures, handcuffed her when she tried to call 911 and threatened to handcuff her 12-year-old son, the suit said.

Officers visited twice more in the following month, went to her husband's workplace three times, wrote to her landlord and contacted the Housing Authority in an unsuccessful attempt to evict her, the suit said.

The city did not respond to specific allegations in the suit but said the Community Action Team was engaged in crime-fighting, not discrimination.

"The team brings neighborhoods and police into partnership to resolve issues involving violent crime, narcotics activity, dangerous or substandard structures and sanitation issues," the city's statement said. "Antioch residents of every background have credited the Community Action Team with helping to restore the safety and security of their neighborhoods' parks, streets and homes."

E-mail Bob Egelko at begelko@sfchronicle.com.