Early leads to the identity of the Tylenol killer evaporated today as more than 100 investigators questioned suspicious persons and employes of stores where the poison-laced capsules were sold.

Capsules found by Kane County sheriff's deputies in a parking lot early Tuesday, before the first deaths from the cyanide-tainted capsules occurred, proved to contain only Tylenol, not cyanide.

The deputies found two six-packs of Tylenol torn open when they pulled into the parking lot of a Howard Johnson's motel and restaurant in Elgin. About 200 capsules were open and white powder was spilled on the ground.

When it appeared the powder was not an illicit drug, the men ignored the boxes. Later one of the men became sick, and the following day the second got sick with symptoms that might have fit with cyanide poisoning.

But a spokesman for the Illinois Department of Law Enforcement said the first tests for cyanide on the capsules proved negative. Another series of tests will still be conducted.

The investigators have also failed so far to discover any incriminating fingerprints "that we can discuss yet" despite careful checks of all the cyanide-loaded bottles of Tylenol, Illinois Attorney General Tyrone Fah-ner said late today.

Investigators were interviewing for the second and third times clerks in stores where the poisoned capsules were found, and were searching through the employe records of the Jewel Food, Osco Drug, and McNeil Consumer Products companies.

Some of the bottles of tainted Tylenol were purchased at Jewel Food and Osco Drug stores in the Chicago area. McNeil Consumer Products is the division of Johnson & Johnson that manufactures the product.

Investigators were also tracking paper trails through shipping receipts and store invoices to try to determine if the killer might have made a bulk purchase of the Tylenol he used to murder seven here.

Meanwhile, psychologists offered competing and sometimes conflicting "profiles" of the supposed killer. Some described him as an unhappy employe trying to get back at his employer. Others said he could not have been an employe trying to get revenge because his targets were random victims.

Most said he was likely to be a white male, middle-aged, and very ordinary in appearance and daily behavior.

Most accounts agreed that the killer is likely to seek attention for his act in some way, and may eventually provide the leads the investigators now lack. Arthur Schueneman of the Northwestern University Medical School said, "The grandiose nature of the crime says he wants to be caught."

"Somebody who commits a crime like that wants attention; otherwise there is no point in doing it. And one day he may get drunk at a bar and talk about it -- that's the way they caught Richard Speck," said Robert Fletcher of the Department of Law Enforcement.

Richard Speck killed eight student nurses in Illinois nearly two decades ago.

Meanwhile, politicians in Washington and Illinois began efforts to make it harder to kill by contamination by asking manufacturers to explore new ways of sealing drug capsules or their packages so that tampering would be obvious to consumers.

The Cook County Board today unanimously passed a measure requiring, within 90 days, that all nonprescription drugs sold in the county be enclosed in sealed containers.

State officials in Illinois also said they were considering a similar measure. In Washington, Arthur Hull Hayes, commissioner of the Food and Drug Administration, asked the over-the-counter drug industry to establish a task force to consider ways of securing drug packages. The Proprietary Association, the trade group of nonprescription drug makers, has agreed to finance such a task force.

Investigators also began to complain yesterday that something of a "black market" in Tylenol is developing in the absence of the ability to buy the product off store shelves.

Fahner said he had received two reports of pharmacists selling Tylenol taken off the shelves but still held in storerooms. "That is wrong," he said. "It puts more of the stuff" back into circulation, making the job of investigators harder, he said.

Last night, he told a news conference that he is mystified about why pharmacists would attempt such sales, which he termed "offensive and potentially deadly." He said he has received no reports of attempted price-gouging in any such sales.

Fahner warned pharmacists that he intends to file civil lawsuits against anyone caught selling Tylenol. "We have the lawsuits drafted and just have to plug in the names . . . . " he said.