John Mark Karr wrote in e-mails that he wanted to have sex with a beautiful, blue-eyed, blond 5-year- old girl in his class in Thailand.

Authorities' fear that he was moving in on her prompted his arrest on murder charges sooner than they had planned.

According to a court document written by an investigator, Karr said in e-mail and phone contacts with a Boulder professor that "he was drawn extremely close to the beauty of the child and desired to have a sexual relationship with (her)."

The document said Karr added that he was having difficulty "getting (her) off of my mind."

Karr also said he was depressed because he could not see her during summer vacation, from mid-July to mid-August.

Classes resumed Aug. 15 and investigators confirmed that Karr was again teaching children. On the same day they learned this, Boulder prosecutors obtained a judge's signature on a warrant for his arrest in the 1996 killing of blond, green-eyed JonBenet Ramsey at her Boulder home.

The warrant was dropped Monday.

Karr's e-mails named the girl in Thailand and others who drew his interest, but the names were deleted from documents released to the public.

Investigators said they were able to determine Karr was having "personal involvement" with at least one.

Using the name Daxis in his e-mails, Karr added that "little girls can have sexuality that is not largely recognized."

He also described two children exposing their navels to him, and massaging someone's foot under a table in the international school's lunchroom.

Court documents said that Thai police twice asked Karr for a DNA sample and he refused. Then he agreed, but sampling supplies were not available.