It's possible he had multiple accounts but seems unlikely, one reason he was caught was because he made a whole bunch of trades on markets related to "year in search", all on one account, and all the trades were perfect. If he was thinking about creating new accounts to obscure himself then he should have at least made each bet he placed on a seperate account.

People (particularly those committing crimes) do frequently overlook things in inconsistent ways, so it's possible. But seems unlikely to me.