SEATTLE (AP) _ Midway through the Sudafed tampering trial of Joseph E. Meling, prosecutors have shown he is a manipulator, blabbermouth, spendthrift, egotist and conniver. Now it's his lawyers' turn - to convince the jury he is not a killer.

On Monday, defense lawyers begin presenting witnesses to bolster their contention that the evidence is too thin to convict Meling of product tampering in the deaths of two people and the near-fatal cyanide poisoning of his wife.

Never in 30 days of monitoring conversations with a hidden microphone or in two months of tapping his parents' telephone did Meling indicate guilt. Nor were incriminating fingerprints or traces of cyanide found.

The most damning evidence was the testimony of two handwriting experts that Meling signed for the purchase of a pound of sodium cyanide on Jan. 11, 1991.

The prosecution contends that the following month, the former insurance agent put a cyanide-filled capsule into a package of Sudafed 12-hour decongestant in an attempt to kill his wife for $700,000 in life insurance. He is also accused of inserting cyanide in five other packages to make it appear a random killer was at work.

Jennifer Meling, 30, narrowly survived, but two others died. The case prompted a nationwide recall.

Since the trial began March 2, the jury has heard stories of strip clubs, feuding families, stormy marriages, doctored computer files, and possible baby-selling by the defendant's uncle, a former psychiatric patient who has forgotten how many times he was married.

Mrs. Meling, an eighth-grade English teacher, filed for divorce but reconciled with her husband after a visiting a friend in Hawaii - the FBI paid the air fare for the trip.

On the stand, she repeatedly insisted that she loved her husband, believed he was innocent and had been convinced to file for divorce by her parents, their friends and FBI agents while in ''an emotional coma.''

By the time her tearful testimony ended, she also said she felt manipulated, used and abused by both sides.

The government's chief informant, Keith Jerome Meling, said his nephew asked him to help ''get rid of his wife'' after Mrs. Meling called authorities for help as the couple quarreled on Dec. 22, 1990.

Keith Meling has a criminal history of bigamy, forgery and bad checks and was diagnosed in the 1970s as a paranoid schizophrenic. He testified he couldn't remember the names of all his six wives, how many times he had been married, how often he had been in jail or whether he once offered to sell his unborn baby for $10,000.

Defense lawyers are portraying Joseph Meling as a victim of circumstances, overzealous investigators and his own big mouth.

Not one witness to date has described him as a friend. Several of his wife's friends said they quit seeing her because they found Meling domineering and controlling.

''You know, she realizes now fully and resents the fact that she's been, you know, she's kind of addicted to manipulation,'' Meling said in a June 1991 taped telephone conversation.

''It's like she is used to it, she grew up with it and, um, when it's gone she looks for it - 'Please manipulate me, please' - and ... she realizes that's a problem.''

Meling's own acquaintances and co-workers testified that practically all he talked about after his wife was poisoned was his fear of being sent to jail - especially after she filed for divorce.

Investigators told Mrs. Meling that her husband frequented topless bars as the couple argued increasingly over spending and sex in late 1990. During the trial, she also learned he sent flowers to strippers, asked them for dates and showed up without warning at their doorsteps.

Since Meling was arrested in August, his wife has visited him in jail at least once a week, but she is still weighing her future with him, said her lawyer, John W. Wolfe.

''She would like to have some closure on it, one way or the other,'' Wolfe said. ''Clearly, the verdict of the jury is going to have some impact on her decision.''

Meling, who is charged with six counts of product tampering, two counts of perjury and three of insurance fraud, faces life in prison if convicted of product tampering.