The London Metropolitan Police on Wednesday arrested a 19-year-old Shetland Islands man who they say is “Topiary,” the most visible figure in LulzSec.

The police news release doesn’t name the suspect. The bust is the second high-profile arrest of an alleged member of the six-man hacking gang. British police last week arrested a 16-year-old they say is “T-Flow” — another prominent member. In June they arrested 19-year-old Ryan Cleary of Wickford, Essex, who allegedly ran an IRC channel used by the group.

LulzSec’s leader, “Sabu,” remained active on Twitter Wednesday morning, but did not immediately acknowledge the arrest of his purported frontman.

Topiary has served as the public face of LulzSec since it came to prominence in May with an intrusion at the website of PBS Newshour, where it posted a false news story announcing that deceased rapper Tupac Shakur had been found “alive and well” in New Zealand. By then the gang had already hacked Sony’s Japanese website, and before that Fox.com — where the group stole and posted 363 employee passwords, along with the names, phone numbers and e-mail addresses of 73,000 people who had signed up for audition information for the Fox talent show The X-Factor.

Subsequent hacks included the Arizona Department of Public Safety and other Sony sites, including one where LulzSec obtained and posted the e-mail addresses and passwords of about 50,000 consumers who’d registered for one of three Sony promotional sweepstakes.

By late June, web vigilantes and rival hackers had exposed what they said were the real identities of LulzSec’s members, and the gang announced on June 25 that it was disbanding. The group emerged from its brief retirement last week to deface a Rupert Murdoch–owned newspaper website.