OMAHA, Neb. (AP) _ A petition drive seeking a grand jury investigation of a black man's death in police custody apparently gathered enough signatures to force the inquiry, the Douglas County election commissioner said Tuesday.

Steve Wiitala said he will give the petitions to District Judge Lawrence Corrigan. Under Nebraska law, if the judge confirms the validity of the petitions, he must call a grand jury to investigate the death of Richard Kellin.

Wiitala said his staff validated 13,504 signatures, or 76 percent of the 17,016 signatures submitted.

''It's unofficial,'' Wiitala said. ''The petition drive is not deemed a success until the presiding judge has a chance to look it over.''

For a successful petition, organizers needed 13,146 signatures from registered voters, or 10 percent of the number of people who voted for governor in the county in 1982.

Omaha police arrested Kellin, 35, on suspicion of disorderly conduct on May 5. He was injured later that day during a struggle with police that reports said began when he pushed a table at an officer.

Kellin died May 9. The autopsy said he died of a skull fracture.

Kellin's wife, Dorcas Denise Kellin, has filed suit in federal court alleging that police used excessive force, which police deny.

A police investigation found no evidence of wrongdoing. The county attorney's staff reviewed the case and no charges were filed.

A citizens group called the Omaha Police Watchdog Committee, headed by black City Councilman Fred Conley and the Rev. Helen Saunders, then started the petition drive.

Wiitala said he would present the petitions Monday to Corrigan, who will have 15 days in which to decide whether to call a grand jury.

Wiitala said it was difficult for his staff to verify the petitions because it recently validated petitions forcing a recall election for Omaha Mayor Mike Boyle. Boyle is up for retention or recall in a special election Jan. 13. Wiitala's staff validated more than 20,000 signatures in that petition drive.