Transcript for New information on the London terror attack

And we have new information to report in that latest London terror plot. Police announcing two more arrests, revealing striking new details, including this, images of the weapons involved. That pink knife, with the handle wrapped in tape. Plus, other evidence indicating that attack could have been far worse. ABC's Jennifer Eccleston in London. Reporter: Chilling new details tonight about the terror attack in London that police now say could have been even deadlier. Police confirming on the morning of the attack, ringleader khuram butt attempted to rent a seven and a half ton truck to ram into pedestrians. The reservation only canceled when he failed to provide payment details. Forcing the attackers to use this smaller white van. Police finding 13 molotov cocktails and two blow torches inside. Tonight, investigators are also appealing to the public for any new information about these pink ceramic knives. If you've seen the three attackers purchasing these knives, then please contact us. Reporter: Police also revealing butt was on bail during the deadly rampage, arrested last year for fraud. Police say someone called a hotline about butt, seen here in this British channel 4 documentary on British extremism, but uncovered no evidence he was planning an attack. Tonight, seven men are now in custody. Police are calling the pace of the investigation unprecedented. But questions continue to linger over the effectiveness of Britain's extremist monitoring. Tom? Jennifer Eccleston with that update from London.

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