(Junction City, OR) -- A 59-year-old man has been sentenced to more than 17 years in federal prison for repeatedly sharing child porn online. Prosecutors say Christopher Lyn Sparks used several social media platforms to distribute explicit material despite prior convictions in 2006 and 2013. He pleaded guilty in December and will remain under lifetime supervision after release. Authorities say Sparks also contacted an undercover agent while offering to trade illicit content.