BUFFALO, N.Y. -- A rape investigation involving Chicago Blackhawks star forward Patrick Kane took a bizarre turn Wednesday when the attorney for the accuser said that an empty paper bag that once held the woman's rape kit had been secretly placed in the doorway of her mother's home.

Kane's attorney, meantime, said both sides in the case have been told that none of Kane's DNA was found "from the waist down" on the woman.

Police officials responded that no packaging is missing from the rape kit.

"Something seriously has gone amiss," attorney Thomas Eoannou told reporters during a news conference, where he held up the wrinkled brown bag that he said pointed to the possibility of evidence tampering.

He said the woman's mother discovered the bag on Tuesday afternoon when she came home from work for lunch. She found the bag folded up between a storm door and her front door, he said.

It was the first time Eoannou has spoken publicly about the case that has been the source of intense speculation and rumour since early August, when Kane was accused of assaulting a young woman in his waterfront mansion after they met at a nightclub.

Kane last week said he did nothing wrong and expected to be absolved. He also apologized for the distraction he has caused his family, teammates, the Blackhawks organization and fans.

Eoannou said the person that left the evidence bag did not knock on the door or ring the doorbell.

"It could have been there a day and a half," he said, because the woman used the back door when she left for work that morning.

He said the bag is authentic, labeled with personal identifying information for the woman, details on where the rape kit was used and the initials of the nurses who administered the kit.

"I have never seen an evidence bag outside of a police lab, a prosecutor's office or a court room, let alone find one in a doorway of a rape victim's mother's home," he said.

"We're hoping to find out how this happened and who had the incentive to modify or tamper with the evidence," he said.

Erie County District Attorney Frank Sedita said Eoannou's claim would be investigated. He declined further comment.

The head of the county agency responsible for maintaining evidence in such cases, meanwhile, said everything given to the agency by the investigating Hamburg Police Department is accounted for.

"This includes the evidence in the rape kit and the packaging itself," Erie County Commissioner of Central Police Services John Glascott said in a statement. "This evidence has been analyzed and reports of that analysis sent to the appropriate agencies."

Hamburg Police promised to co-operate in any investigation, but stood by its handling of evidence.

"The Hamburg Police Department has documentation that unequivocally demonstrates that its handling of the evidence and the integrity of its chain of custody of evidence in this case is unassailable," a statement from the suburban Buffalo department said.

Eoannou said he wants the FBI or state police to probe how the bag left the custody of investigators. It's not clear how the bag got to the mother's home or what effect it may have on the investigation, he said.

An FBI official in Buffalo said the agency does not conduct independent investigations on local matters.

"Absent a specific allegation of a federal crime or a request from a local agency for assistance, the FBI will not be opening an investigation," Assistant Special Agent in Charge Holly Hubert said.

Kane did not travel to Detroit with the rest of his team for Wednesday's Blackhawks game against the Red Wings, a person familiar with the situation told The Associated Press. The person spoke on condition of anonymity because Kane's travel plans were not publicly announced. Kane played on Tuesday and it's common for players to rest when their team plays consecutive days in the preseason.

Kane's attorney, Paul Cambria, said he would welcome an investigation of the bag incident.

"Only someone who is unhappy with the DNA results would have a motivation to claim that it's compromised," Cambria told The Associated Press. "We are obviously quite pleased with the DNA results."

A noted defence attorney who is not involved in the Kane case said that bag could simply have been carelessly discarded if the evidence it contained was placed in a new bag, which would not affect the evidence itself or the case.

On the other hand, attorney Steven Cohen said, "I would be concerned that any breaches in the chain of custody or security of evidence, or any potential that may exist for the tampering of evidence, could adversely affect my client's case."

Eoannou said he hopes the person who left the bag comes forward.

"I have obviously my grave concerns as to what's going on here," he said.