DETROIT -- Not guilty pleas have been entered in Michigan on behalf of seven of nine members of a militia group that prosecutors claim plotted to kill police officers.

The seven were arraigned Wednesday in U.S. District Court in Detroit. The hearing was delayed while a lawyer for the alleged ringleader, 44-year-old David Brian Stone, traveled to the courthouse from Miami.

Stone was among nine members of the Hutaree militia arrested after a series of raids in Michigan, Indiana and Ohio. A court document says an undercover FBI agent and a cooperating witness were part of the federal probe.

Hearings to determine if they'll be released on bail were expected later Wednesday for Stone and six others. One suspect's bond hearing will be Thursday.

The ninth suspect is in court in Indiana.