The prosecution contends that William and Marita Riethmiller paid Mr. Patrick $8,000 to organize the kidnapping. Attorneys for the other two defendants have contended that their clients merely helped Mrs. Riethmiller rescue her daughter from a roommate's control.

Miss Riethmiller has denied on the stand that her roommate was a lesbian and said the whole issue was irrelevant to her victimization. ''I think that's an invasion of privacy, and that's not what I'm here for, I don't think,'' she said. The roommate, Patty Thiemann, 20, was called to testify and also said she did not think their private life was relevant to the case. Prosecutor's Beliefs at Issue

An added factor in the case is that Prosecutor Simon L. Leis of Hamilton County is known as a conservative on social issues. In the past he has called homosexuality immoral, and in court in this case he has referred to lesbianism as ''unnatural.''

In her testimony, Miss Riethmiller told of being deprived of food and sleep in her forced stay in Alabama, while her mother was present.

She has filed a $2.75 million civil suit against her parents, accusing them of joining a conspiracy to kidnap, mentally torture, intimidate and sexually abuse her.