New Zealand police said Saturday that they believe a 22-year-old British tourist who has been missing for a week was murdered, and they will lay charges against a man they detained earlier in the day for questioning.

Grace Millane was on a planned yearlong trip abroad that began in Peru. She arrived in New Zealand last month and was last seen on the night of Dec. 1 entering a central Auckland hotel with a 26-year-old man.

Police said they brought that man into the central Auckland police station on Saturday afternoon for questioning. Later in the day, police said they planned to charge the man with Millane's murder and he would be held in custody until his first court appearance on Monday.

Detective Inspector Scott Beard said he told Millane's devastated father, David Millane, on Saturday that they believe Millane was killed. The father had traveled from Britain to New Zealand earlier in the week.

Beard said they don't know where Millane's body is located but they're determined to find it and return it to her family.

"I know that the thoughts of all New Zealanders will be with Grace's family tonight," Beard said.

Police have been conducting a scene examination at a unit in the hotel. Beard said they're also examining a vehicle and want to figure out where it has been driven over the past week.

Millane had been staying at a backpacker hostel in Auckland and left some of her belongings there. Beard said she met a man for a couple of hours on Saturday evening before surveillance cameras showed them entering the CityLife hotel at about 9:40 p.m.

Her birthday was on Sunday but she didn't contact her family.

Five days later, on Friday, David Millane arrived in New Zealand and spoke with media.

"Grace is a lovely, outgoing, fun-loving, family-oriented daughter," he said, adding that she was usually in touch with her family every day.

"She arrived here on the 20th of November, and has been bombarding us with numerous photographs and messages of her adventures," Millane said. "We are all extremely upset, and it's very difficult at this time to fully describe the range of emotions we are going through."