U.K. police have said  man who put  bomb on  London subway train bought most of  parts for the bomb online. Police have accused  18-year-old Iraqi refugee of planting  bomb on a busy commuter train on September 15. The bomber left his device on  packed subway carriage during  peak rush hour. The bomb exploded at Parsons Green subway station at 8.20am. It caused burns to  face and body of 30 passengers. Police said there would have been more casualties if  bomb had worked properly. It didn't detonate fully so there was less harm to humans than there could have been. Police said  bomb contained, "knives, screws, glass and similar items to increase  likelihood of death."
 bomber bought many of the ingredients for his device from  online shopping site Amazon. One of these ingredients was several hundred grams of  explosive called TATP. This is also called "Mother of Satan" because it is so powerful. Police said  bomber used it to create "maximum destruction". Reporters later checked Amazon for  ingredients and were shocked to find that  site directed them to other things that could be used to make bombs, in  "items frequently bought together" tab. Amazon said it will work to stop this happening. It said: "In light of recent events, we are reviewing our website to ensure that all these products are presented in  appropriate [way]."