EUDORA, Kan. -- First it was an unexploded Drano bomb in a mailbox, but now police in Eudora have learned there was another pop-bottle bomb, and this one did explode.

The explosion was forceful enough to knock the mailbox off its base at a home at 13th and Acorn streets. No one was injured when the devices, which were made of liquid Drano and aluminum foil, went off.

Because of the bottle bombs were found in mailboxes, the oostal inspector will now be involved. Local media reports indicated that the Postal Inspection Service was offering a reward of up to $1,000 for information leading to the arrest and conviction of those responsible.

A neighbor said he heard the boom on Thursday night, and saw the damage on Friday morning. The debris has all been carted off by police, but the neighbor said the back of box was blown out and the side split.

"This is something that a lot of pranksters will do to fill the fill the bottles up to watch the bottles explode or blow mailboxes up," said Greg Dahlem, Eudora police chief.

In the first incident, police said the mailman was on his last stop of the day at about 2:20 p.m. on Thursday when he found a 2-liter Dr. Pepper bottle in a mailbox.

"When we first looked at it, it appeared to be just anti-freeze -- green-type anti-freeze," said Dahlem.

Fire crews descended on the neighborhood for the next 2½ hours to investigate the find.

Once the Olathe, Kan., bomb squad relieved the pressure on the bottle, authorities found what's commonly known as a Drano bomb, Dahlem said.

Interestingly, KCTV5 has learned from neighbors that school teachers lived at both of the homes in the city limits where the bombs were found, although they work for different districts.

Media reports also indicated a possible third bomb found just outside of Eudora.