The cornerstone of the defense's case was that the Manitowoc County Sheriff's Department had a strong motive to frame Steven Avery.  Looking at the facts, though, might lead to a different conclusion.

Two officers of the Sheriff's Department, Lt. James Lenk and Sgt. Andrew Colborn, had been called to a deposition related to Avery's 2004 lawsuit.  They also volunteered to aid in the Halbach investigation.  Lenk found the Rav 4 key in Avery's bedroom, with Colborn on the search team.  This is what laid the groundwork for the theory that they would have motive to frame Avery.

In 2004, Avery filed suit against Manitowoc County, Thomas Kocourek, and Denis Vogel.  Kocourek had been Sheriff at the time of Avery's false conviction, and Vogel had been the District Attorney.  Both were retired at the time of the lawsuit, and the Halbach case.  In the suit, Avery attempted to prove that both men had intentionally ignored other suspects, including Gregory Allen, the actual perpetrator.  In an attempt to prove this, Avery's legal team had found a number of documents in Vogel's case file suggesting Allen as a suspect.  There was also evidence that multiple members of the Manitowoc Police Department and investigative team had attempted to discuss Allen as a suspect, but Kocourek would not allow them to pursue any other leads.  Vogel knew of these concerns, and chose to ignore them.  They also refused to supply Avery's legal team with information about Allen as a suspect. (Upon review, however, the DOJ found these files had been properly disclosed to defense.)  Avery claims at least $1,000,000 and up to $18,000,000 in punitive damages from Vogel and Kocourek.  He claims at least $1,000,000 and up to $18,000,000 in compensatory damages from Manitowoc County, Vogel, and Kocourek jointly.

Avery had a strong case against Vogel and Kocourek.  Members of both of their staffs had attempted to follow leads other than Avery, and been shut down by their bosses.  So how do Lenk and Colborn fit into all of this?  Colborn was one of those staff members.  In the mid 1990's, he received a phone call from Brown County, stating they had an inmate claiming he had committed an assault in Manitowoc County that another man was in jail for.  According to deposition testimony in 2005, Colborn did not recall at that time the name of the detective from Brown County, and he did not recall that either Avery or Allen's names had been specifically mentioned.  However, according to Chief Deputy Eugene Kusche's testimony, Colborn had told Kocourek about the phone call.  Kusche had heard in the mid 1990's that Colborn did in fact mention that he believed it was Allen and not Avery who was responsible for Penny Beernstern's assault.  Kocourek told him that they had the right guy, and he should not concern himself.  Once again, Kocourek was intentionally ignoring information that Avery might be innocent, despite the attempts of his staff.  

On September 11, 2003, Steven Avery was freed from prison.  During a conversation about his release, Colborn told his new supervisor, James Lenk, about that phone call.  Lenk told him to write a report to document it, and they passed the information on to the county's current sheriff.  Had Lenk not chosen to document the information, it most likely never would've been known.  Because he realized the weight of the information and chose to document it, there was yet more proof that Kocourek was ignoring information that would've led to Avery's release.  There is no indication, anywhere, that Lenk knew about the phone call prior to Avery's release.  

Lenk and Colborn were not facing any negative repercussions due to Avery's lawsuit.  The Wisconsin Department of Justice had already cleared the department of criminal wrongdoing.  Lenk and Colborn were not personally named in the lawsuit, and would not have been financially or criminally affected by its outcome.  They were merely called to give testimony proving that Kocourek had been ignoring information provided by his officers.  In light of that information, it is hard to imagine that they would participate in a plot to frame Avery.  The two men being sued had long since retired, and had no more authority over Lenk and Colborn.  If they truly did participate in a plot to frame Avery, it would've been incredibly risky.  It presumably would include at the very least somehow obtaining access to Teresa Halbach's key, somehow transferring Avery's DNA to it, and planting it in the bedroom while a Calumet County officer was watching them.  Of course if you believe more than the key was planted, the risks become exponentially greater.  One of the bullets found in the garage was conclusively linked to Avery's gun, which had been in storage at the State Crime Lab or Calumet County since November 6.  Would they be able to drive to Madison, sneak into the storage room, fire a round from Avery's gun, collect the bullet, and sneak out without detection?  If caught in such a high-profile investigation, with officers from two counties, the State Crime Lab, the fire department, dog search teams and diver search teams, and the Department of Justice all on the scene, they would certainly face severe consequences.  Jail terms, steep fines, and lawsuits even greater than the one currently being faced.  Would they be willing to risk all that to save two men who no longer even worked for the county, and had already been publicly exposed?  It is a question only they can answer, but it seems unlikely.  Once it becomes clear that Lenk and Colborn were not in any way civilly or criminally responsible in Avery's lawsuit, the risk seems to outweigh the reward.

Could they have had pressure from the County?  The documentary claims insurance companies were refusing to cover damages from the lawsuit.  However, a review of the case files shows only a motion filed by State Farm Insurance relating to Kocourek.  He had attempted to get his home owner's insurance policy to cover the lawsuit, and State Farm protested and filed a motion refusing coverage.  No such document exists from Manitowoc County's insurer.  In fact, Strang confirmed in a recent interview the insurance did in fact pay Avery's settlement.

Reviewing the information related to Avery's lawsuit, it is very hard to find reason for anyone currently working for Manitowoc County to take the extreme risk of framing Avery.  At least five other agencies, including the FBI, Department of Justice, and Calumet County, were involved in either the search or the investigation.  The likelihood of getting caught, with that many agencies participating in such a high-profile case, would be high.  The benefit to anyone personally working the Halbach case would be nonexistent.  We cannot definitively prove Lenk and Colborn would not have been willing to take that risk, but it certainly seems most people would not.