When Patricia Ryan talks about the dangers of cults, she draws from two very different kinds of painful personal experiences.

Her father, the late representative Leo J. Ryan of California, was shot and killed six years ago yesterday in Guyana by followers of Jim Jones, the leader of the Peoples Temple cult that Ryan had gone to investigate.

Two years later, Shannon Jo Ryan, her sister, became a follower of Indian guru Bhagwan Shree Rajneesh and later went to live in his commune in central Oregon.

Yesterday, a memorial service at the Capitol marked the anniversary of the Jonestown massacre, in which 913 persons died when Jones led his followers in a mass suicide-murder ritual following the ambush on Ryan and his group at a jungle airport. While Patricia Ryan's remarks at the service did not mention her sister's involvement with a cult, she later said she was troubled by it.

"I'm concerned about it, wary about it," Ryan said in an interview. "Obviously, she has been subjected to some kind of brainwashing."

Ryan said she is in contact with her sister, however, and she visited the commune in Oregon two years ago for her sister's wedding to another Rajneesh follower.

The commune was clean and organized and the people were friendly, Ryan said, and she saw no signs of drugs or fear as one may have expected to see at Jonestown. At the same time, the leaders knew ahead of time of her visit and were prepared for it, she noted.

"I don't know if it another Jonestown could happen at the Rajneesh camp," but there is a fear of that whenever people blindly follow a leader, she added.

Ryan said her sister says the guru would not ask his followers to do what those at Jonestown did and "just laughs and says I'm crazy" when questioned about what she is doing.

"We cannot afford to forget what happened in Jonestown only six years ago," Ryan said in her remarks at the memorial service, sponsored by the Cult Awareness Network and several Jewish organizations. About 30 persons attended the service.

The appeal of cults is that they "falsely promise easy answers to complex problems of life," said Ryan, 31, a legislative assistant to Rep. Richard L. Ottinger (D-NY). Ryan said she went to high school with three of the Jim Jones followers who died at Jonestown and described them as "idealistic but confused."

Congressman Ryan has been awarded a congressional gold medal, and a White House ceremony has been scheduled for Nov. 29.

Among those at the service yesterday were Norman and Dorothy Humphreys, whose daughter has been a member of the Rev. Sun Myung Moon's Unification Church for eight years. "The worst was when she spent three years in Detroit fundraising for the church ," Mrs. Humphreys said. "She was out all night . . . going around to the bars."

"We've had time to adjust. It used to be very hard," Mr. Humphreys said. The cult network is important in helping other parents adjust when their children join cults, he added.

The Humphreys' daughter was one of thousands married by the Rev. Moon in a mass ceremony in New York in 1982, but she lives in Santa Barbara and her husband lives in New York. "She says they get along fine," Mrs. Humphreys said with a smile.

Genny Ayers, a 29-year-old former Hare Krishna, was passing out programs at the service yesterday. When she joined the Krishna group, she said, she had dropped out of school and "was doing a lot of searching, for Utopia . . . .They were offering an ideal life."

Ayers said her regimen as a Hare Krishna included getting up a 2 a.m., taking cold showers, chanting mantras for two hours and then spending all day, every day pinning flowers on people at airports. "I thought I was serving God," she said.

Ayers said her mother had her taken away and flown to another state for deprogramming, an experience that was frightening at first because "your whole world is blasted out from under your feet."