A Canadian who was arrested in northern Thailand for spraying paint on an ancient wall says she's sorry for what she did and terrified about what comes next.

Brittney Schneider, 22, was in Chiang Mai last Thursday when she said she and some others got "ridiculously drunk." They started to walk back to their hostel, but came across a bottle of spray paint and picked it up.

"I came to as I finished writing the B and I stopped because I knew it was bad," she said Tuesday in an email interview with The Canadian Press. "But it was already too late."

Security camera footage shows Schneider, who is from Grande Prairie, Alta., and Furlong Lee, 23, spraying paint on the walls of the Tha Pae Gate in the city of Chiang Mai.

They have been charged with vandalizing registered ancient artifacts, which carries a penalty of up to 10 years in prison and a fine of one million baht ($40,000).

Police said Lee, who is from Liverpool, England, admitted that he wrote "Scouser Lee" on the wall, while Schneider wrote the letter "B" underneath it.

The 13th-century Tha Pae Gate is part of an ancient wall that forms a square around Chiang Mai's inner city.

After they sprayed the wall, they walked back to the hostel and went to sleep, Schneider said.

"The next morning we woke up and were sitting beside the pool and I just remembered what we did and looked over to one of the guys from the night before and said, 'OMG, we spray-painted a wall last night. I'm so scared we're going to get in trouble."'

She said she had gone upstairs to her room to call a friend when a hostel employee knocked on her door and said there was an issue downstairs.

"My heart dropped. I knew," said Schneider. "I walked downstairs, opened the door and there were like seven police officers standing there.

"They showed me a video and asked if it was me in the video spray-painting the wall. I said, 'Yes, it was me."'

Schneider said they were arrested and taken to the police station where they spent the night before court.

"The judge said we could face up to 10 years in prison and/or a fine of $40,000," she said. "We had the chance to get bail that day, but it was too late at home so I couldn't get the bail. I spent three nights in prison and got bailed out yesterday."

Schneider said her mother and aunt have arrived in Chiang Mai and, while she's thankful they're there, she said she's not OK mentally.

"I'm terrified for my life. I'm so sorry for what I did, beyond sorry," she said.

"I'm just so overwhelmed and just want to go home."