State privacy laws are especially protective of psychologists' records, aiming to guard patients' confidences.

Those laws may be helping to shield a killer's identity, at least temporarily. Police say an investigation into the ferocious stabbing of a Manhattan psychologist has been slowed because detectives are barred from reviewing the slain therapist's patient records without a court order.

The killer slashed Kathryn Faughey 15 times with a meat cleaver and a 9-inch knife in her Upper East Side office Tuesday evening. A funeral was set Saturday for Faughey, 56.

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Detectives were trying to determine whether the killer was a patient of Faughey or Dr. Kent Shinbach, a psychiatrist who worked in the building, came to Faughey's rescue and was maimed by the slasher.

But investigators have been unable to access patient records because of state and federal privacy laws. The killer told the building's doorman he was there to see Shinbach, but the psychiatrist didn't recognize him, police said.

As the Manhattan district attorney's office worked with police Friday to get patient information, investigators searched for evidence, removing nine boxes from Faughey's office, scrutinizing footage from neighborhood security cameras and following up on tips made to a hot line.

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"There's a lot of forensic evidence, a lot of analysis that has to be done, and that's all going forward," Police Commissioner Raymond Kelly said. "A lot of processing going on now as we speak, but we have not gotten anything back."

Kelly said he wasn't sure how long it would take police and prosecutors to get permission to see information in the patient records, which are protected under the federal Health Insurance Portability and Accountability Act and state confidentiality laws.

"The HIPAA laws are, no question, a challenge to law enforcement," Kelly said. "This is certainly not the first time where the issue of privacy comes up against concerns and requirements as seen by law enforcement."

The district attorney's office said it had already been able to obtain some patient information, but the work was ongoing. Spokeswoman Barbara Thompson said she couldn't comment on whether subpoenas would be issued, or whether officials would go to court to get the records.

Authorities have to prove in court that they have a legitimate cause to obtain patient information.

HIPAA laws, which went into effect in 2003, provide a floor for patient confidentiality. State laws are followed if they are stricter, as they are in New York, legal experts said. The laws are particularly stringent on psychologists' records.

David Truemen, a psychologist and health law professor at Columbia University, said the laws allow police to get information about specific patients. But without a suspect's name -- as in the Faughey case -- it would be difficult to gain access to multiple records.

"They can't do a fishing expedition," he said. "If they show probable cause, they can get records of individuals, but they can't just go get a list of patients and all their information."

Eugene O'Donnell, a professor at John Jay College of Criminal Justice, said it isn't impossible for authorities to obtain such records, but investigators must go through proper channels.

"It's more time-consuming, and it may slow the investigation, but there are legitimate safeguards built into the law, and exceptions built in, too, for cases where it's needed," he said.

Shinbach's assistant has been working with police to contact patients, mostly to ensure they were safe, Kelly said. Faughey's husband also was providing information.

On Thursday, detectives traveled to Pennsylvania to interview William Kunsman, a friend whom Faughey had offered to help with personal problems. They had spoken on the day she was killed. He was not considered a suspect, police said.

New details emerged Friday as police shed more light on events leading up to the stabbing, saying the killer sat in a waiting room with another patient for nearly a half-hour before the bloody attack. The slasher arrived at 8 p.m., then sat in the waiting room with a female patient of Shinbach's until she went into his office around 8:30 p.m.

Sometime after that, the killer entered Faughey's office and attacked her. Shinbach came to her aid and was assaulted and robbed by the killer, who then tried to force Shinbach's patient into a bathroom. She fended him off, and he left the building at around 9 p.m.

The suspect left two bags near the basement door through which he escaped. The bags were filled with adult diapers, women's clothing, rope, duct tape and eight knives, police said.

Shinbach was taken to New York-Presbyterian Hospital/Weill Cornell Medical Center with slash wounds on his head, face and hands. The hospital declined to release any information about Shinbach on Friday; police believed he remained in serious but stable condition.