Wilputte Alanson Sherwood, 63, had been sought for fleeing his probation out of the Phoenix area in 2005. He was subsequently named the Maricopa County Adult Probation Department's most wanted sex offender, the U.S. Marshals Service reported.
U.S. Marshals spokesman Matt Hershey said Sherwood's capture was considered a high priority for the service, which is tasked with tracking down unregistered sex offenders under the federal Adam Walsh Child Protection and Safety Act.
Hershey said reports out of Arizona alleged Sherwood may have had sexual encounters with thousands of individuals, including hitchhikers and runaways.
"We would consider him a major case," Hershey said.
U.S. marshals and members of local and Phoenix-based fugitive and child predator apprehension teams arrested Sherwood without incident as he was leaving the Most Holy Redeemer Catholic Church, located at 100 Diamond St., late Sunday morning, the U.S. Marshals Service said.
"He was very quiet, didn't want to say much," Hershey said. "He wasn't very happy."
Sherwood faces state charges for fleeing probation and state and federal charges for failing to register as a sex offender, Hershey said.
Sherwood was convicted in Maricopa County in 1993 of sexual conduct with a minor, attempted sexual exploitation of a minor, and dangerous crimes against children, according to the U.S. Marshals Service.
Prosecutors alleged he "kept extensive logs and videotapes of many of his sexual encounters with numerous underage boys," the U.S. Marshals Service said.
Sherwood was released from prison in 2003, and U.S. Marshals have now discovered he had been living in San Francisco for about two years, according to Hershey.
Hershey said Sherwood had no family here, but "was very familiar with this area from his past."
"He had been out here numerous times throughout his life," going back to the 1960s, Hershey said.
Sherwood remains in custody in Alameda County jail awaiting extradition proceedings to Arizona, according to Hershey.