Brasilia, Brazil ? A 17-year-old American exchange student missing in Brazil was seen trying to hitchhike to the capital the day she disappeared, Brazilian authorities said Wednesday.

MyKensie Martin, a senior at Summit High School in Bend, Ore., was reported missing Sunday, said Kreg and Judy Roth, of the Rotary Youth Exchange Program in Bend.

A witness spotted the girl Sunday evening on the side of a highway leading to Brasilia from the town of Unai, about 80 miles from the capital, said Unai police Detective Celso Avila Prado.

Martin told the witness she was on her way to an event sponsored by the Church of Jesus Christ of Latter-day Saints in Brasilia and did not have enough money for a bus ticket, Prado said.

The Roths said Martin left her host city of Carmo do Paranaiba early Sunday to travel 38 miles by bus to Patos de Minas, where she attends a Mormon church.

Investigators said that instead of returning, she changed her bus ticket to travel 150 miles to Unai, Kreg Roth said Tuesday.

Martin’s parents were scheduled to fly to Brazil on Wednesday.

Unai police visited hotels in the city of 65,000 people, but found nobody else who had seen Martin, Prado said. He said there was no immediate sign that a crime was committed.