On Thursday, two more teens were taken into custody, 19-year-old Clayton Christopher Pierce and his brother 17-year-old Clinton Harry Pierce.
Investigators say the teens allegedly tried to put a plastic bottle filled with liquid in a mailbox on November 29. However, the bottle was too big to fit inside and was thrown on the front lawn of the home and exploded.
Police say the teens later returned on December 29 and placed another liquid filled bottle inside the mailbox, causing it to explode.
However the teens did not know the homeowner had set up a video camera, which showed the teens in a silver Ford Mustang pulling up to the mailbox and placing the bottle inside.
The four suspects have been charged with one count of malicious use of an explosive device and two counts felony conspiracy.
They were released from jail under a $20,000 secured bond and modified to the custody of their parents.
During the investigation, authorities say they gathered information about a vehicle fire on June 9, 2009.
Arrests made in that case led investigators to the suspects in the mailbox bombings.
Pugh along with two other teens, Devon Johnson and Ryan Lewis, have been charged with felony burning of personal property and conspiracy.
Johnson and Lewis were given a $10,000 bond, modified to the custody of their parents.
Investigators say additional charges are pending in other jurisdictions in regards to similar crimes.