In life, she was the thoughtful one, the hard worker, the devoted wife. $1She brought birthday cookies to the man who ran the corner newsstand, baked cheesecake to share with her fellow musicans.

But her death was marked by the trappings of New York City's latest Gothic murder: dark passageways, unmarked doors, dungeon-like subterranean rooms. A precipitous drop down an air shaft from a sixth-floor rooftop. The naked body of a young female musican found at the Metropolitan Opera House.

Stories headlined "Murder at the Met" and "Phatom of the Opera" described how the body of free-lance violinist Helen Hagnes Mintiks, 30 -- who was playing in a pick-up orchestra at the Met for the two-week run of the Berlin Ballet -- was found Thursday morning lying across two boards in a ventilation shaft, 60 feet below the roof of the opera house. Mintiks had left the orchestra during Wednesday evening's performance, and a fellow musician told police later that Mintiks had said she had an appointment for "an artistic discussion" with dancer/choregrapher Valery Panov, the star of the show. She never returned after intermission.

After completing a day-long autopsy yesterday, New York Chief Medical Examiner Elliot Gross said that the death was "the result of a fall," and that Mintiks was alive when she was thrown from the roof, fracturing her skull, ribs and limbs. A police spokesman said yesterday that there was "no appearance of a sexual assault," and no sign of strangulation.

"Her hands were bound behind her back and her ankles were bound together with a rope and portion of a garment," Gross said, but would not comment on what kind of garment was used on whether it was part of Mintiks' clothing. The victim's shoes were found on the roof, and police say that "other clothing" was found in the vicinity of the killing.

Members of the all-free-lance orchestra wre phoned during the day Thursday and told to report to work early in order to be available for police questioning. Teams of detectives swept through the theater questioning the orchestra members, house staff, dancers and in particular Panov, who police say is not a suspect. (He said Thursday that he did not know Mintiks and had no appointment with her.) A police spokesman said yesterday that a team of more than 25 detectives will finish interviewing "every employe at the Met" -- over 800 people -- by today.

Because access to the sixth-floor tar-and-gravel-covered rooftop is possible only by either leaping off a high catwalk or walking through a maze of hallways leading to a single, unmarked door, police suspect that the murderer was familiar with the labyrinthine layout of the Met.

Speculation has arisen among Met employes that the killer could be or might once have been a fellow employe. The Berlin Ballet opens at the Kennedy Center next Wednesday, and Met officials said yesterday that for the Washington engagement, the Met is sending its own veteran stage crew to aid in the presentation.

Orchestra members who said they knew the murdered woman spoke well of her on Thursday. One described her as the "loveliest, sweetest person." Others used words like "cheerful," "good," "giving," and "friendly." She was the sort of person who made a long-distance phone call to her parents every Sunday night.

"Helen was the kind who would come to your house for dinner and bring along the "dinner," said Kerry Voight, a bassoonist and friend.

Helen Mintiks was the youngest of three sisters raised on a poultry farm in the tiny community of Aldergrove, B.C, Canada. Her parents emigrated there from Finland.

"When Helen was 2, she'd hear songs on the radio and then play them on the parlor piano," her sister, Belcie Hill, told the Associated Press. "Mum and Dad put a great deal of time and effort and money they didn't have into Helen's music."

For eight years, until she was 19, Helen and one or the other parent commuted weekly in the family truck to Vancouver -- a 76-mile round-trip journey-for violin lessons. "Her success did not surprise me," said her teacher, Douglas Stewart. "I expected it of her. She was an outstanding, clever girl, an exceptional child."

She was concertmaster of the Vancouver Junior Philharmonic and a soloist with the Seattle Symphony while still a teen-ager. She left Canada at 19 to enroll at the Julliard School in Manhattan, where she earned a bachelor's and a master's degree. While working as a counselor one summer at a camp outside Montreal, she met her future husband sculptor Janis Mintiks.

She later studied in Italy and at the Institute of Advanced Musical Training in Montreux, Switzerland, but moved to New York when the renowned violinist Nathan Milstein agreed to accept her as a student. She married Mintiks a year later, in 1976. They led a quiet life. By all acccounts, the marriage was a happy one.

The winner of numerous international awards, Helen Mintiks lived with her husband on New York's West Side, not far from Lincoln Center, and was frequently hired by independent music contractors to play at limited engagements such as the 11-day Berlin Ballet visit in New York.

Music industry sources said that if her goal was to become a famous soloist, she most likely, at age 30, had failed. But if she wished to join a major symphony orchestra, her experience as a top freelancer would have been no handicap.

The New York press has charged hard after the story. Friday's New York Post carried the headline "Phantom of the Opera" and "Cops Hunt Sex Killer at the Met." In a front-page story, the Post reported that Mintiks' colleagues "believed her brutal death was linked to a violent scene in the ballet.

"A 37-minute segment, 'Miss Julie,' includes three violent rape scenes in which the attacker goes berserk and tears the clothes off his victim. . . .

"It can't be a coincidence. I was emotionally involved when I played that piece,' said well-known violinist Benard Zeller," according to the Post story.

(In the Metropolitan Opera's program, however, no mention of rape is made in the synopsis of the story.)

For all the headlines and speculation, terror does not stalk the Met. The management hired some 50 extra security personnel for Thursday night's -- and subsequent -- performances. But otherwise, it is business as usual in Lincoln Center. The lines of ticket buyers are long, the house staff is calm, the dancers are dancing, the musicians are playing.

Some of the mothers of local children hired for the ballet said Thursday that they would remove their children from the production for fear of another murder. But not one of those stage mothers actually pulled her child out of the ballet that night.

Jane Hermann, the Met's presentations director, annoyed at the press interviews that some of the mothers had given, stated that "six little girls were left by their mothers at the stage door to wander around" by themselves on Thursday night, two hours before they were scheduled to enter the building, so that Hermann said, the mothers could themselves attend the evening's performance.

The children were not scheduled to arrive at the theater unitl 9 p.m. When a Met employe found them several hours earlier, a baby-sitter was hastily recruited to watch over them. The Met has ordered that the children can travel about the theater only in groups and must have an escort to ride in the normally unattended elevators.

The audience spent Thursday evening's two intermissions strolling about the Lincoln Center complex gossiping about women's dresses, the weather, the price of quiche, the ballet and of course the murder. Interviews with audience members and more than 20 employes of the theater revealed no one worried about safety.