Story highlights London attacker named as Khalid Masood, a 52-year-old Brit

Masood thought to be lone wolf, but ISIS took responsibility for the attack

(CNN) The London attacker, Khalid Masood, is believed to have acted alone in carrying out what UK officials are calling a "copycat," or "ISIS-inspired" attack.

At the same time, a tweet from ISIS shows the group is taking responsibility for the incident, referring to Masood, though not by name, as a "soldier of Islamic state."

How can both be true?

ISIS may be losing money and losing ground in some of its biggest strongholds, but they have one powerful, unpredictable weapon: Social media. With the rise of online or remote radicalization, would-be extremists don't ever need to make contact with ISIS figures, or even deeply understand their motives, to carry out the next big attack.

There are still some big questions in the London investigation. Masood was known to police as having ties to extremism, and he had a violent history. But so far, no direct connection has been made between ISIS and the attacker. The reality is, there doesn't need to be one. Some of the most devastating attacks in the Western world as of late have been of the "lone wolf" variety, including the shootings in Orlando and San Bernardino; and the truck attacks in Nice and Berlin . ISIS media regularly encourages these attacks and recommends locations and methods.

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