Lawyers for Wayne Williams, blamed for the murders of two dozen children and young men in the late 1970s and early '80s, have asked to perform DNA testing on dog hair, human hair and blood.

A motion seeking the testing was filed Tuesday in Fulton County Superior Court. Lawyer Jack Martin said in May that the defense planned to make the request.

Between 1979 and 1981, 29 blacks, most of them boys, were killed in the Atlanta area, spreading fear throughout the region.

Williams was convicted in 1982 of murdering Nathaniel Cater, 27, and Jimmy Ray Payne, 21, and sentenced to two consecutive life terms. Afterward, officials declared Williams responsible for 22 other deaths, and those cases were closed.

Williams, who is black, has contended he was framed. He has maintained that officials covered up evidence of Ku Klux Klan involvement in the killings to avoid a race war in the city, which investigators have denied.

Witnesses testified during his trial that Williams was seen with some of the victims, but he was convicted largely on fiber evidence.

His appeals have been repeatedly rebuffed. A federal judge last month rejected Williams' request to reconsider evidence he claims points to another suspect.

In the filing Tuesday, Martin asked to perform DNA tests on hair recovered from the clothing of Cater and Payne to compare it with dog hair recovered from Williams' German shepherd, Sheba.

Martin also asked to test dog hair linking Williams to murders that prosecutors used to establish a killing pattern during the trial, even though he wasn't charged in them.

In May 2005, former DeKalb County Police Chief Louis Graham reopened five murder cases, but the investigation stalled and was discontinued after Graham resigned this year.

Fulton County District Attorney Paul Howard said Tuesday he has not decided whether to oppose the request for DNA testing, which could take a few months.