Juan Duran, 44, was named Wednesday in an at-large warrant with statutory sodomy in the first degree. The incident is alleged to have occurred in Duran's car sometime from 1999 to 2002, when the boy was 10-13 years old, police said. The boy is now 15.

At the time, authorities said, Duran was at St. Francis de Sales Church.

Federal authorities also are investigating Duran, in connection with a second alleged sexual encounter with the boy during a Chicago area retreat, police added.

Duran left the priesthood's Dominican order at about the time of the alleged incidents and may now be in Bolivia, police said.

Police said Duran had befriended the boy and his family. After the alleged incidents, the boy told relatives, officials explained.

The boy's family reported their allegations to the archdiocese, which initiated a criminal investigation by notifying the state's child abuse hot line, police said.

Jim Orso, spokesman for the archdiocese, said he knew little about Duran, except that he was ordained in 1996 and was assigned in Memphis before St. Louis.