By Brian Maass

PARK COUNTY, Colo. (CBS4) – CBS4 has learned that a former Park County Deputy Travis Threlkel has now joined a lawsuit against the Park County Sheriff’s Office and Sheriff Fred Wegener over the fatal 2016 eviction that left Deputy Nate Carrigan dead.

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Cpl. Nate Carrigan and Martin Wirth (credit: CBS)

According to federal court documents, Threlkel joined the federal lawsuit Wednesday. Threlkel was one of six deputies sent to the home of Martin Wirth Feb. 24, 2016, to evict Wirth from his home.

When deputies, including Threlkel, entered the home, Wirth opened fire, killing deputy Carrigan and wounding two other deputies — Kolby Martin and Cpt. Mark Hancock — who both survived. Wirth was also killed in the shootout.

Travis Threlkel (credit: LinkedIn)

Carrigan’s family, along with Martin, filed the federal lawsuit saying the eviction operation was botched and mishandled from the start. They called command decisions made that day “grossly negligent” and the deaths and injuries “entirely preventable.”

Park County Sheriff Fred Wegener (credit: CBS)

They pointed out that Wirth had made multiple threats against police and contend a SWAT team should have been used for the high-risk eviction.

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Contacted Wednesday afternoon, the Carrigan’s attorney, Don Sisson, was asked about Threlkel joining the lawsuit.

“Deputy Threlkel was victimized by the dangerous decision making of the Park County Sheriff’s Office, Sheriff Fred Wegener, and Cpt. Mark Hancock, that was entirely preventable,” Sisson said.

Park County Master Patrol Deputy Kolby Martin with trauma surgeon Rebecca Vogel, MD, at St. Anthony Hospital (credit: St. Anthony Hospital)

Sisson went on to say that Threlkel joined the lawsuit because he “could no longer stand idly by and felt he had to take action by joining this lawsuit to ensure that what happened to him, Kolby Martin and Nate Carrigan never happens to another deputy in Park County.”

According to online profiles, Threlkel began working for the Park County sheriff in 2014 but left his job with the sheriff’s office in January of this year.

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CBS4 Investigator Brian Maass has been with the station more than 30 years uncovering waste, fraud and corruption. Follow him on Twitter @Briancbs4.