Investigation of Stockholm bombing is still going on with more tips and information coming in, said Vice Chief Prosecutor Agnetha Hilding Qvarnstrom Thursday.

"About 400 people contacted us with tips and many wanted to leave information about what they see," Qvarnstrom said at a press conference at the Security headquarters in Stockholm.

Qvarnstrom said they are still not 100 percent sure about the identification of the man who blew himself and his car with bombs last Saturday in Stockholm city center.

She said that they are cooperating with seven bomb experts from the U.S. Federal Bureau of Intelligence (FBI) and police in the United Kingdom.

Anders Thornberg, director of the Swedish Security Service SAPO said at the press conference that they also cooperated with Stockholm police and all the relevant sectors across the country as well as those from FBI and the British police.

The experts have examined the ingredients of the remains of the bombs.

"We have a good understanding of the ingredients of the bombs, but I cannot say more than that," Thornberg said

According to their investigation, only one bomb in the man's body exploded while the rest did not.

Thornberg said the speculation is that there must be something wrong that prompted the man ignited the bomb earlier.

Swedish media also found that the man whose name was Taimour Abdulwahab went to a shop to buy explosive ingredients in Tranas in southeast Sweden's Jonkoping region where his family live.

Earlier report also revealed that a walkie talkie was found not far from the dead man's body which indicated that either there was an accomplice or the device is used to explode the bombs.

Thornberg said this investigation will last much longer time because they got large amount of information which needed time to analyze.

He also said that they are assessing the threat situation constantly with concerted efforts and the threat level remains the same as that in October when Sweden raised it from the previous level.

Last Saturday two explosions took place in Stockholm center, one was a car explosion and the other was a man who exploded himself.

Earlier reports also say that Abdulwahab had been trained in Iraq and might be brain-washed.

His neighbor all thought he was a nice man who didn't talk much.