But their efforts to help her were rebuffed - even an offer to hide her in another state.
Testimony in Mr. Doan's murder trial in a Clinton County courtroom showed that physical and verbal abuse had become harsher in the months and days before her disappearance on Aug. 29, 1996.
But Mr. Doan's attorney, John Rion, said none of the anecdotes about the violent fights was founded.
Miss Culberson's boss, Desiree Gruber, testified that she saw Mr. Doan slam Miss Culberson against a pickup truck in the parking lot of her Wilmington business in May 1996.
Mrs. Gruber said she was alarmed in July 1996, when Miss Culberson recounted how Mr. Doan had beaten her on the head with a space heater.
''I began to get angry ... and she let me know she had pressed charges,'' said Mrs. Gruber, owner of G&G Hair Studio in Wilmington. Miss Culberson, 22, worked as a nail technician at the salon.
Miss Culberson filed misdemeanor assault charges that July. Prosecutors say the charges may have been Mr. Doan's motive to kill her.
Mrs. Gruber said she asked Miss Culberson why she continued to see Mr. Doan, even after filing charges against him.
''She said, 'It was just easier,''' Mrs. Gruber told the jurors.
''I said, 'We can hide you out somewhere, you can go someplace,''' Mrs. Gruber said. ''I tried to get her to leave, and she said she couldn't do that.''
Choking back tears, Mrs. Gruber recalled how Miss Culberson feared Mr. Doan would kill her mother and sister if she left.
''It was the only time Carrie cried,'' Mrs. Gruber said. Family and friends of Miss Culberson wept quietly in the courtroom as Mrs. Gruber struggled to compose herself.
Another witness, Tonya Whitten, testified that on Aug. 26, Mr. Doan drove with Miss Culberson to the outskirts of Blanchester, where he held her at gunpoint for roughly five hours. Mrs. Whitten testified that Miss Culberson had confided in her about the incident, and Mr. Doan's subsequent phone call to apologize.