Illinois Attorney General Tyrone Fahner said today that investigators trying to track the cause of seven Tylenol cyanide poisonings are assuming that a killer "physically has gone into the stores and replaced" safe medicine with cyanide-loaded bottles.

Fahner, who is heading a 15-agency task force, said authorities are not close to finding a suspect, but that the probe's few common threads point toward a single killer, most likely a "disgruntled worker."

Fahner told the Los Angeles Times that preliminary analysis of tainted Tylenol capsules recovered by police suggests that more than one killer may be involved.

Fahner said some of the capsules were put together more "artfully" than others, indicating " . . . that maybe we've got two or three people, some more careful than others . . . , or maybe just one person without much patience."

As hundreds of investigators began showing photographs of what they called known "kooks" to employes at area drugstores and distribution centers, Mayor Jane Byrne banned the sale of Tylenol in the city.

Food and Drug Administration investigators also confirmed that a Tylenol bottle pulled off the shelf at a suburban drugstore late Friday contains cyanide, placing the poison in at least four area stores.

The latest bottle of poisoned Tylenol, found in an Osco Drug Store in Schaumburg, contained 14 cyanide-tainted capsules of the 50 in the bottle.

The new bottle was found in the same northwest suburban area as all of the previous bottles except one and from the same drugstore chain as two of the other bottles.

Fahner, in an interview, said no pattern has been found that would make it seem possible for the crime to have taken place at the distribution level rather than the store level.

The Tylenol in Illinois arrived from two manufacturing plants, in Pennsylvania and Texas, and went to about 100 distributors. The distributors, he said, then turned it over to about 11,000 retailers. Since there are no shared factors among the tainted Tylenol capsules found so far, Fahner said, "Trying to trace a common path through that is probably not going to do it." Fahner said his agents on the streets today were questioning shopkeepers, truck drivers and clerks, asking them about each other, about disgruntled workers and about any "strange persons" who might have lingered in stores or bought multiple boxes of Tylenol. He said he has ruled out the possibility of a manufacturing defect in the Tylenol, despite reports today that some cyanide is used in the plants where the painkiller is manufactured.

There is, he said, direct evidence of tampering with capsules, and the bottles with cyanide also contain safe capsules. Those two findings, together with test samples at the plants, make it unlikely that a manufacturing mistake caused the seven deaths, he said.

Fahner said that several other suspected cases of poisoning investigated today have proved to be unconnected to the Tylenol killings. A man in Texas who died suddenly, a women in Cleveland who had a small amount of cyanide in her blood and a young man in the Chicago suburbs who died unexpectedly Thursday were all found to have no tainted Tylenol capsules connected to their cases.

So far, the only bottle containing cyanide-packed Tylenol that was not found in the northwestern suburbs was the one found near the body of the seventh victim, a stewardess who lived within the city limits of Chicago.

Paula Prince, 35, a flight attendant, was found Friday in her apartment a few blocks north of the Loop.

She apparently came home Wednesday night from work and took an "Extra-Strength" capsule. The bottle was found open on the basin in the bathroom, and her body was found on the floor a few feet from the bathroom, apparent evidence that the cyanide killed her quickly.

The batch number on the bottle was one not previously associated with the tainted Tylenol. It was 1809MA. The other two lots recalled by manufacturer McNeil Consumer Products, a subsidiary of Johnson & Johnson, were MC2880 and 1910MD, amounting to more than 264,000 bottles.

The death of Prince and her connection to the Tylenol case was announced by Byrne at a televised news conference early this morning.

The mayor said the city, despite the dismay of the manufacturer, would take every Tylenol product off the shelves, including tablets, capsules and liquid forms.

Today, acting "under broad emergency powers in the city health code," she banned Tylenol in Chicago. Friday the mayor had asked area residents to take their Tylenol products and turn them in to police and fire departments. By mid-afternoon, the Associated Press said, 554 incidents of people bringing Tylenol to precinct stations had been recorded.

Though the FDA warned consumers nationwide not to take any Tylenol in capsules, several other states also took strong action on their own. North Dakota banned sales of Tylenol. Colorado ordered all stores to remove all Tylenol, regular or extra-strength, from the shelves, and Massachusetts asked shop owners to stop selling Tylenol products.

Poison control centers in Chicago and elsewhere in the country were deluged with questions from callers worried about cyanide poisoning.

The poisonings began Wednesday morning, when 12-year-old Mary Kellerman, staying home from school with the sniffles, took a cyanide-laden capsule and died.

Three members of one family who took Tylenol from the same bottle also died Wednesday. Then two young women died Thursday after taking tainted capsules.

Today, the Tylenol killer's first victim, the 12-year-old girl, was buried.