ATLANTA (AP) _ Authorities from three states investigating a series of mail bombs have been shown the high-tech tools the federal government is using in the case.

A special computer network reserved for major cases and sophisticated laboratory tests, including procedures for DNA identification, were demonstrated Wednesday during a meeting of authorities from Atlanta, Savannah, Birmingham, Ala. and Jacksonville, Fla., said FBI spokesman Diader Rosario.

It was the first meeting involving federal, state and local law enforcement representatives from all four cities in which mail bombs were received during a series of attacks in December that killed a federal judge and a civil rights lawyer.

Those attending the meeting also were briefed on evidence gained from a public hotline set up to receive tips in the case, Rosario said.

Rosario said today there will be further such meetings, but no date has been set for the next one. He said the FBI, which is coordinating the investigation, does not want to have the meetings too often.

''Every time you meet you pull people out of the field, where they can do more good,'' he said.

Rosario said the investigation has not narrowed to any particular area, and still is in full swing in Georgia, Alabama and Florida.

Robert Vance, a judge on the Atlanta-based 11th U.S. Circuit Court of Appeals, was killed Dec. 16 when a mail bomb exploded at his home near Birmingham, Ala. Two days later, Savannah Alderman Robert Robinson, an attorney who did work with the NAACP, was killed by a similar bomb. Authorities intercepted bombs sent to the 11th Circuit courthouse in Atlanta and an NAACP office in Jacksonville before they could explode.

A letter to Atlanta television station WAGA-TV last week claimed a group calling itself Americans for a Competent Federal Judicial System was responsible for the bombs and threatened more violence.

The letter writer expressed anger over crimes committed by blacks against whites and also made an apparent reference to a school desegregation case in DeKalb County.

FBI agents searched DeKalb County schools during the Christmas holidays, looking for clues to the bomber and for bombs, according to news reports. The FBI and the school system have refused to comment on the reports.

Georgia Gov. Joe Frank Harris said at a news conference Wednesday that he would be willing to post a reward for information in the case, if police ask him to do so. He said he has received no such requests.