May 2010: A series of unexplained explosions rocked the Longfellow neighbourhood of Minneapolis, USA, on May 15. Authorities say they are unable to "solve" the case because they don't know what caused the blasts.
April 2010: A couple was killed in a powerful blast inside their house in the Indian state of Mizoram on April 20. Police said they had to shut the case because they were clueless about what could have triggered the explosion.
April 2010: A mysterious blast destroyed a building in West Philadelphia, USA, on April 30. The force of the blast was so strong it shattered the windows of a pizza outlet about a block away. When asked if he knew what could have exploded, the owner of the house Charles Johnson said, "No, I don't have anything in there. I have a van, that's it." A massive investigation was launched, but there is no word yet on what caused the explosion.
March 2010: Authorities in Portland, USA, say they have no idea what caused the huge boom that shook homes. A Portland Fire and Rescue spokesman said, "nobody could find anything."
