Ryan Ackroyd, a 25-year-old Briton, does not have a high profile like Hammond. But the online persona that the FBI believes him to be, the hacker "Kayla," certainly does. "Kayla" has received significantly more press coverage than other LulzSec/Anonymous hackers, most likely because "she" claimed to be a teenage girl -- a rarity in the hacker community.
Kayla played a key role in LulzSec's February 2011 hack of security consulting firm HBGary, which was executed in retaliation for one of its CEOs claiming he could unmask Anonymous. Soon after, she gave an online interview to Forbes, in which she said she was a 16-year-old girl living in an English-speaking country (though she claimed not to be from Britain) and being raised by her father, who is himself a programmer.
The Forbes article also noted that there were persistent rumors on the hacking forums Kayla frequented that she was in fact a mid-20s man from New Jersey. Kayla denied it, but law enforcement had similar suspicions -- in September 2011, Scotland Yard arrested two men in their 20s who they believed to be jointly using the Kayla identity. Although those men were not named in news reports, one of them was from Doncaster, England, which is where Mr. Ackroyd is reported to be from. The Associated Press also reports that Ackroyd was arrested last year in connection with LulzSec activities.