The firm shut down on Jan. 31, just days before a key court decision on whether the alleged file-sharing defendants could claim damages from the firm and lead plaintiffs.
MediaCAT, the IT company referring adult company clients, also has shut down.
The moves come after a number of legal maneuvers went awry and its firm's principle, Andrew Crossley, said he was a victim of death threats and DDoS attacks on the firm's website. In December, its first case was lost due to a variety of technicalities. Later, 27 defendants who had received letters of demand said both ACS:Law and MediaCAT declined to put forward any evidence in a case that was eventually dropped.
Some of the defendants have even warned that they'll sue Crossley for harassment
Crossley had earlier speculated that he might close the firm down following threats to his family. Later, he confirmed that speculation. "I have ceased my work .... I have been subject to criminal attack. My emails have been hacked. I have had death threats and bomb threats," he said, according to a report.
ACS:Law from the get-go had problems with ISPs that refused to disclose names and addresses of customers identified through their IP addresses.
Crossley and ACS:Law came under fire two months ago after the personal details — including names, phone numbers and addresses — of thousands of Britons leaked online via an attack on the company's website.
Many also saw their names or postcodes linked to porn videos that MediaCAT was claiming they had illicitly downloaded.
British regulators, according to reports, have been investigating ACS:Law's practices before the firm closed down. It wasn't clear whether a probe will be carried on against Crossley following the the firm's closure.
Regulators investigating the breach say that ACS:Law could be levied a file of more than $800,000 if it were found to have been holding the information on alleged file-sharer identities insecurely.
While ACS:Law may have closed shop, another law firm has recently taken up the task of sending letters of demand.
Many who had had their cases dropped by ACS:Law received a letter from GCB Ltd, a new law firm. In court, Judge Colin Birss questioned Crossley about his relationship to GCB.
Crossley admitted that the founders of GCB had previously been employed by him at ACS:Law