San Augustine County authorities arrested a man Friday wanted out of Washington on three child sex assault warrants.  Sheriff's office Chief Deputy Gary Cunningham said his office received a tip that Sherman Clay Roberts, 58, was living in San Augustine County. Roberts has three warrants for his arrest out of Washington; two for rape of child and one for failure to register as a sex offender.  Once deputies positively identified Roberts, they placed him under arrest for a new charge of failure to register, as he had not registered as a sex offender in San Augustine County.  Cunningham said the charges date back to 1992. The failure to register warrant was obtained in 2008.  Cunningham said he is working with Washington authorities to see if they will extradite Roberts.