Lab tests that linked a cyanide death to a Sudafed cold capsule took two weeks longer than usual, a state official said, and an FBI agent said that may have delayed the issuing of a drug-tampering warning.

Two people in Washington state have died of cyanide poisoning and a third was seriously injured after taking Sudafed capsules.The incidents prompted the over-the-counter drug's manufacturer, Burroughs Wellcome Co. of Research Triangle Park, N.C., to pull it from stores nationwide on Sunday.

Two suspicious-looking Sudafed 12 Hour capsules have been sent to an FBI laboratory in Washington since the recall. Tests on at least one were planned Tuesday, said agent William Gore, who heads the FBI's investigation here.

Authorities said all three poisonings and the discovery of two more capsules that may have been tampered with occurred in the Tacoma-Olympia area.

No one has been arrested, and authorities have not revealed a possible motive.

Tumwater Police Chief Mike Vandiver told Seattle's KIRO-TV on Monday his department is looking at one person, but he refused to identify that person or say whether he or she is a suspect. He said the individual has been under investigation since the first poisoning, on Feb. 2, in which the victim survived.

Meanwhile, David Predmore of the state toxicology lab told Seattle's KOMO-TV that it took his lab two weeks longer than normal to determine that the first of the two deaths was the result of cyanide poisoning.

He said the process can be done in two days. He said he could not explain the delay.

But Dr. Barry Logan, the lab's director, said there are six lab workers to handle 6,000 cases a year, and because of heavy caseloads, investigators usually wait 10 to 14 days for test results.

Kathleen Daneker, 40, of Tacoma died on Feb. 11. Authorities learned on March 1 that her death was the result of cyanide poisoning and that she had taken Sudafed. They issued a drug-tampering warning the next day.

Stan McWhorter, 44, of Lacey, who also took a Sudafed capsule, died of cyanide poisoning on Feb. 18. Gore said authorities might have issued a warning before that if they had known the cause of Daneker's death sooner.

"It's all hypothetical," Gore said Monday. "But one would assume we would have taken action if we were notified earlier. We would have reacted on the 15th or 16th the same way we reacted on the 1st."