This picture released by the FBI shows the mangled remains of a pressure cooker
The twin blasts at the Boston Marathon this week, that left three people dead and over 170 injured, show how devastatingly effective pressure cooker bombs can be.
The two hand-made bombs were packed with explosives and stuffed with shards of metal, ball bearings and nails and then placed in duffel bags on the ground. Investigators in the US said the explosives were planted inside pressure cookers which were then stuffed with shrapnel to cause maximum injury.
The blasts turned the festive race into a hellish scene of chaos, fear and confusion in Boston.
In India, terror group Lashkar-e-Taiba (LeT) used pressure cookers to kill 200 people in the Mumbai train blasts on July 7, 2007. They placed seven pressure cookers in local train compartments to target peak hour traffic.
The Indian Mujahideen used the pressure cooker bomb in the Varanasi blast in 2006 that killed seven people.
"They don't raise any suspicion and are readily available. They are lethal as the shrapnel stuffed in them can inflict immense injuries because of the pressure," explained AA Khan, former chief of Mumbai's Anti-Terror Squad or ATS.
These bombs have been used by many terror outfits, included the Al-Qaeda, which also had a detailed tutorial in the 2010 issue of its online magazine on how "the pressurised cooker is the most effective method" for making a simple bomb.
There have been pressure cooker bombings in Pakistan and Afghanistan too and a pressure cooker was one of the three devices used in the attempted bombing at Times Square in New York in May 2010.
While American investigators are still trying to figure out whether a foreign or domestic group is responsible for the attack in Boston, the cause of concern is how easily an innocuous pressure cooker can turn into an agent of death in the hands of a terrorist.