TUCSON, Ariz. (AP) -- A man from Germany has been sentenced to nearly 16 years in federal prison in Arizona for a child sex tourism offense. Prosecutors say 51-year-old Karsten Puschmann, of Kiel, was sentenced Friday in U.S. District Court in Tucson. He received a 189-month prison term Friday followed by lifetime release with stringent sex offender conditions, including the condition that Puschmann register as a sex offender. Puschmann pleaded guilty in January to traveling with intent to engage in illicit sexual conduct. An investigation revealed that Puschmann used the Internet to negotiate and plan a trip to Mexico to engage in sex acts with six different children between the ages of 5 and 11. Authorities say he traveled from Europe to Arizona for that purpose and was arrested upon his arrival in Tucson.