The author of an influential but controversial blog criticising companies for holding patents solely to sue for infringement has been unveiled as a senior in-house lawyer at IT giant Cisco Systems, writes The Recorder.

Richard Frenkel, a director in Cisco's intellectual property (IP) group, unmasked himself on Saturday (23 February) as the author of Patent Troll Tracker following an anonymous threat via email to identify him.

The blog – which Frenkel has temporarily suspended – has become required reading for many US patent attorneys.

Winston & Strawn IP litigation partner David Bloch said: "I have a case in Texas where one of my co-counsel sent me a long excerpt from the Troll Tracker blog because he had learned something about the plaintiff that he hadn't known,"

Weil Gotshal & Manges patent litigator Edward Reines agreed that "most IP litigators keep an eye on Troll Tracker".

The news comes after the author's identity was made the subject of a bounty, first reported by Recorder affiliate IP Law & Business. The bounty – initially set at $5,000 (£2,548) but eventually raised to $15,000 (£7,643) – was offered by Chicago lawyer Raymond Niro of Niro Scavone Haller & Niro.

Niro reported on Monday (25 February) the reward had not yet been claimed, saying: "Whoever did it did it not for the purposes of making money but rather for the purposes of exposing him."

Niro had a contentious relationship with the anonymous blogger since a Troll Tracker post criticised Niro last year. After Niro filed a patent suit for a client against Google, Frenkel was among the first to report that Scott Harris, a Fish & Richardson partner based in San Diego, was listed as the inventor on the patent while his firm was also representing Google. Harris resigned shortly after.

Critics including Niro said the blog's credibility had been brought into question by Frenkel's position at Cisco, which holds 5,000 patents worldwide, with 7,000 more in applications, and is a member of the Coalition for Patent Fairness, a lobbying group including dozens of the largest IT companies in the US.

However, patent attorneys who regularly read the blog disagree, with Reines adding: "It provides very reliable and prompt information about what's going on in patent litigation."

The Recorder is a US sister title of Legal Week.

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