The state Department of Justice said Friday that an internal investigation into work done by six disciplined state Crime Laboratory employees has found "no instances where faulty forensic test results were presented in court against criminal defendants."

The agency also said that the probe by the Division of Criminal Investigation (DCI) found "no evidence of systemic problems that would bring the reliability of the laboratories into question."

In a statement, Attorney General J.B. Van Hollen said the investigation, which was prompted by a September complaint by Brookfield criminal defense attorney Jerome Buting, showed that "the six personnel matters at issue were known to and investigated by the Wisconsin Department of Justice long before Mr. Buting wrote his letter. They did not affect the reliability of forensic results in any criminal cases."

Buting said he was disappointed in the probe.

"It's the whitewash that I feared but expected," Buting said, adding that he planned to further pursue his concerns at the federal level.

Buting's complaint was based on disciplinary records of six state Crime Laboratory employees.

In his 11-page complaint, Buting said the shoddy work of the analysts may have jeopardized forensic test results and should be independently investigated.

Buting, who represented convicted murderer Steven Avery, argued in the complaint that the DOJ is obliged to launch an independent inquiry into the work of the employees as a condition of the $578,000 in federal funds the crime lab has received since 2005 under the Coverdell Forensic Science Improvement Grants Program.

In a letter to Buting, the DOJ rejected that argument, saying that most of the incidents occurred before the state received the Coverdell grants and that none constituted "serious negligence or misconduct substantially affecting the integrity of forensic results."

Gabriel Oberfield, a research analyst with the Innocence Project in New York City, interpreted the federal law differently.

He said it requires that agencies receiving the funding conduct "independent" and "external" investigations into allegations of misconduct, even if the alleged incidents predate acceptance of the grants.

"It's clear there still has yet to be a real investigation," Oberfield said.

The complaint cited six disciplinary letters to employees in which their names were blacked out. DCI Special Agent Richard Luell said his investigation included interviews with their supervisors and a review of personnel files and investigative reports.

He said the actions prompting the discipline were "isolated" and not related to any "systemic problem" at the Madison and Milwaukee laboratories and that the Crime Laboratory's own internal processes identified the problems.