SANDPOINT — A Craigslist advertisement offering a 4-year-old boy for sale has been traced back to a Sandpoint teen with a bad sense of humor and too much time on his hands.

“He denied it at first and then after talking to him a little bit, he admitted that he had done it,” Lt. Corey Coon said on Tuesday.

The teen’s identity was not disclosed.

Authorities in Spokane, Wash., initiated the investigation after the posting appeared on the free online classified ad website in February, according to the Spokesman-Review.

The ad, which included a photo of a young boy, was taken down by Craigslist, but a site user managed to save the text of the ad’s copy, the newspaper reported.

The ad offered the child for $5,000. Coon said the teen copied a random image of a child from the Internet to include with the ad.

The story garnered international attention and prompted a far-reaching investigation by detectives from Spokane County.

Coon said authorities there obtained search warrants to obtain Internet Protocol addresses, the numerical labels assigned to devices linked to a computer network. The suspect IP addresses led them to Idaho and the teen.

“The short version, essentially, is that he was at home and thought it would be funny, a practical joke,” said Coon.

While waiting for the IP addresses, Coon said detectives in Washington spent a considerable amount of time running down leads.

“They were chasing leads all the way over to Seattle and all over the place,” he said.

Coon said the teen wondered what kind of reaction he would get from posting the ad. The suspect might get more than he bargained for, though.

Criminal charges are being weighed in Idaho, although Coon said it was unclear if he would be charged with offenses in Washington. The potential Idaho charges range from fraud to violations of the state’s adoption laws.

Coon expects to forward his findings to the Bonner County Prosecutor’s Office next week.

“If I can find a code section that’s adequate for it, I’ll recommend they do something and we’ll leave it up to the prosecutor to make the final say,” said Coon.