A fire at an abandoned mobile home has been ruled an arson, Gwinnett fire investigators said. A reward has been issued for information leading to the arrest and conviction of the person or people responsible. A passerby called 911 at 8:47 a.m. Monday to report smoke coming from an abandoned trailer at 194 Howe Lane, in the Gwinnett Estates mobile home park in unincorporated Loganville. The fire caused minor damage to the inside of the trailer and sent moderate smoke through the sparsely furnished structure. Witnesses told investigators from the Gwinnett County Department of Fire and Emergency Services that older teenagers and adults are known to frequent the trailer and might be involved with vandalism and drug activity. Signs of graffiti and broken windows littered the mobile home.