Hacker Cosmo, a member of the UGNazi hacker group, appears to have been arrested in connection with the May 21 breach of the billing and customer support provider WHMCS.

Softpedia's Eduard Kovacs reports that the FBI has arrested Cosmo, quoting a fellow hacker as saying, "Last time was just questioning, but this time he's actually being held. No other word from him."

The same hacker also said another member of the group, called Josh, hasn't been online for days.

"Apparently, Cosmo was actually the one who social engineered Hostgator employees in order to get the access information to WHMCS systems," Kovacs writes. "In the meantime, law enforcement also seized the hacktivists’ website (ugnazi.com) and Cosmo’s Twitter account. Ironically, one day before his arrest, Cosmo posted a picture with a message that read 'Arrest one of us; two more appear. you can't arrest an idea.'"

"In an interview with Cosmo posted on CyberWarNews on Wednesday, Cosmo says 'as of now, there is no confirmed arrests or upcoming court dates for any of us that I know of,'" writes Web Host Industry Review's Nicole Henderson. "However, also on Wednesday, @UGNaziNews retweeted the Softpedia article without denying the charges."

Still, Henderson notes, "A blog post on The Malware Lab says Josh and Cosmo may have been arrested even earlier on May 2, 2012, which could mean that the Comcast and WHMCS hacks were carried on without them."