An alleged member of a criminal organization in Malden has pleaded guilty to drug trafficking and distribution charges. Joshua Joyner, 21, was one of 11 men arrested during searches in March as part of the investigation into the Maplewood Organization, a criminal group based in Malden, according to prosecutors. The investigation netted more than 400 pounds of marijuana headed to Malden from California and multiple illegal firearms. Earlier this month, Joyner pleaded guilty to charges of distribution of a Class D drug and conspiracy to traffic more than 100 pounds of marijuana, according to an announcement from the Middlesex district attorney’s office. The other 11 defendants have been indicted and await trial.