Law360 (August 9, 2021, 11:16 PM EDT) -- Following a six-day trial before U.S. District Judge Rodney Gilstrap, an Eastern District of Texas jury on Monday found that AT&T, Sprint, Verizon and T-Mobile did not infringe inventor Joe Andrew Salazar's patent on a wireless communication device.

The jury, which deliberated for about four hours before returning its verdict, found unanimously that Salazar did not prove by a preponderance of the evidence that the companies infringed his patent, but also rejected the companies' argument that the patent at issue is invalid, according to minutes of the trial and the jury verdict form.

"We appreciate the jury's hard work and verdict of noninfringement," defense counsel Todd Landis of Williams Simons & Landis PLLC said. "Our clients presented compelling evidence in this case. It was a pleasure to try the case for all of them."

Counsel for Salazar did not immediately respond to a request for comment Monday.

Salazar claimed the major carriers all infringed a patent he was issued in 1998 on a wireless communication device through their sale of phones made by Taiwan-based electronics giant HTC Corp, which intervened to defend the case on behalf of the cellphone companies.

Salazar previously sued HTC over the same patent in 2016, but a jury eventually cleared HTC of infringement. Salazar argued the new case was different enough for a new trial, and Judge Gilstrap agreed.

In its motion to intervene, HTC said it wanted to halt "Mr. Salazar's serial and unfounded accusations of infringement" and that Salazar was seeking at least $30 million. The company said that in the first lawsuit Salazar only sued the manufacturer of the accused products — HTC Corp. — and made a "conscious decision" not to sue HTC America, the U.S. subsidiary that imported and sold the phones in the U.S., or the companies he eventually sued in his second complaint.

When he did file the second complaint, Salazar merely substituted in the new defendants and changed the venue while otherwise brining identical infringement claims for the same patent, HTC said.

The new suit was filed in June 2019 and amended the next month claiming the infringement was deliberate and willful or done with willful blindness by the companies selling and marketing the HTC phone and/or by inducing others to buy, use and sell them.

The patent-in-suit is U.S. Patent No. 5,802,467.

Salazar is represented by Geoffrey Patton Culbertson of Patton Tidwell & Culbertson LLP, Dariush Keyhani and Frances H. Stephenson of Keyhani LLC and Alan Joseph Robertson of Sloan Hatcher Perry Runge Robertson & Smith.

The cellphone companies are represented by Todd Eric Landis and Fred Irvin Williams of Williams
Simons & Landis PLLC and Tom Gorham of Gillam & Smith LLP.

The case is Salazar v. AT&T Mobility LLC et al., case number 2:20-cv-00004, in the U.S. District Court for
the Eastern District of Texas.

--Additional reporting by Andrew Karpan. Editing by Bruce Goldman.