Today, the circle of tragedy was completed. John Lennon's 5-year-old son became a man.

"I told Sean what happened," Lennon's widow, Yoko Ono, said in a statement. "I showed him the picture of his father on the cover of the paper and explained the situation. I took Sean to the spot where John lay after he was shot.

"Sean wanted to know why the person shot John if he liked John. I explained that he was probably a confused person."

In Mark David Chapman's own words, he was confused Monday night when he stepped out of the shadows of a vestibule at Lennon's fashionable Manhattan apartment house, called to Lennon and emptied his snub-nosed revolver into the former Beatle.

"Most of me didn't want to do it, but a little of me did. I couldn't help myself," a police source quoted Chapman as saying immediately after the shooting.

Today, police were still trying to figure out why Chapman -- a former Jesus freak, amateur rock musician, mental patient and unemployed security guard -- flew here from Hawaii last week for what Manhattan Assistant District Attorney Kim Hogrefe called "a deliberate, premeditated execution."

The suspected motives are as bizarre as the shooting itself. According to a police source, Chapman complained after the shooting that he didn't like the way Lennon autographed an album for him six hours earlier.

Police are also working on a theory -- related by a former friend of the accused murderer -- that Chapman was outraged in 1965 when Lennon told an English journalist that the Beatles were "more important than Jesus now."

The police source said the 25-year-old suspect might have been inspired by a Salvador Dali print in the living room of his Honolulu apartment that is interpreted by some as depicting the assassination of Lincoln.

Another theory is that Chapman may have been disillusioned that his idol, a musical Horatio Alger who wrote a song titled "Working Class Hero," had become a conspicuous consumer, with investments that included luxury apartments and purebred Hereford cattle.

While police pondered these and other possible motives, Lennon's body was removed from the city medical examiners's office at about noon and taken to a private funeral home for cremation tonight. There will be no funeral; instead, Ono announced a prayer vigil for Lennon this Sunday at 2 p.m. and suggested that people pray whereever they are at the time.

In a probate petition filed today in Manhattan Surrogate Court, half of Lennon's estate was left to "my beloved wife," who was named executrix. A trust fund was to get the other half of the estate, which the four-page will valued at $30 million though published reports put Lennon's worth as high as $235 million.

The will warned that any beneficiary filing suit to increase his or her portion of the estate "shall receive nothing whatsoever."

Outside the fashionable Dakota cooperative apartment house where Lennon lived, fans kept a vigil for the third successive day. They brought more flowers, more candles, more old Beatles songs, more tears. By midday the crowd numbered more than 300, all paying their respects to the man whose tunes had provided the score for their own screenplays of life, all mourning the end of an era.

With the sorrow came money, donations to the Spirit Foundation, a charitable organization that Lennon established in 1979 with a $100,000 grant. The foundation helps abused children, orphans and the aged.

Through a spokesman, Lennon's widow asked fans to send donations to the foundation instead of sending flowers to the couple's apartment. A spokesman for the law firm of Kimmelman, Sexter and Sobel, which manages the foundation, said he did not know how much money had been pledged or donated.

Chapman, meanwhile, is undergoing psychiatric evaluation at Bellevue Hospital here. He is being held under a "suicide watch" in a small cell, according to a hospital spokesman.

All the furniture except the bed has been removed for his own protection, the spokesman said. She described the room as having a barred window fogged with opaque paint the admits a filmy light from a courtyard. A television set in a nearby dayroom has been turned down so that Chapman cannot hear reports about Lennon.

Marvin Stone, a ward doctor at the hospital, described Chapman as "a little bit depressed. He would like to know how his family is doing. He has asked about his wife and his mother." Though Stone said Chapman's appetite is "a little off," he added that "at the moment [Chapman] doesn't seem to have any active plans for suicide. He asked for less noise."

According to Dr. Robert Goldstein, former director of Bellevue's forensic psychiatric wing, doctors at the hospital will determine through interviews, therapy and observation whether Chapman "is faking mental illness. Sometimes a person can put on a brief act for an interview but he can't do it 24 hours a day."

Chapman is charged with second-degree murder, the most severe charge in New York State because first-degree murder carries a possible death penalty, and capital punishment is illegal here. Chapman could receive a life sentence if he is found competent to stand trial and is convicted. He has entered no plea pending the psychiatiric evaluation.

An official of the Manhattan district attorney's office explained today why Hogrefe, the assistant district attorney, erroneously told a Manhattan criminal court judge on Tuesday during Chapman's arraignment that the suspect had 12 prior arrests and four convictions.

May DeBourbon explained that when Chapman was arrested, the FBI confused him with another man -- William Alan Chapman -- whose height and physical description roughly match those of Lennon's accused killer. A closer check revealed that the other Chapman has a small mole on his face, a tattoo and several small scars on his hand.

"We sent someone downstairs [to the criminal courts lockup] to check Chapman for the identifying marks but he didn't have them," said DeBourbon. It was later learned that the other Chapman is in an Ohio prison.

As a result of the confusion, Judge Martin H. Rettinger held a second arraignment an hour after the first one. He did not change his orders.

The mixup "in no way affects the strength of the people's truth or the evidence in this case," DeBourbon said.