John Ferak

USA TODAY NETWORK-Wisconsin

MANITOWOC - Would a tightly connected group of small-town cops fabricate multiple clues to frame Steven Avery for murder?

Many of those who are convinced of Avery's guilt in Teresa Halbach's death scoff at the notion of evidence being planted. Critics of Avery's trial lawyers suggest it would be impossible to pull it off. To them, police officers would never engage in such reprehensible conduct.

"Obstruction of justice, that's felony behavior," special state prosecutor Tom Fallon argued in the courtroom in 2007. "Misconduct in office for a police officer, tampering with evidence, the list goes on and on. I'm going to risk my career over that? I think not."

RELATED: Zellner imposter tricks Department of Justice

RELATED: Did crime scene access taint Avery murder case?

On the other side are those who believe that evidence-planting in Avery's case isn't far-fetched. No more than a half-dozen law enforcement people may have been involved in a scheme to frame Avery, and evidence-planting doesn't require a wide-ranging, far-reaching conspiracy, they say.

NEWSLETTER: Get the latest Steven Avery news in your inbox

SUBSCRIBE NOW: Follow us today on YouTube

Lawyers Jerry Buting and Dean Strang suspected four sheriff's employees at Manitowoc County of being involved in an evidence-fabrication scheme against Avery, pretrial court transcripts show. Two were detectives James Lenk and Dave Remiker. The others were then-Sheriff Ken Petersen and Sgt. Andrew Colborn.

The prosecution objected, arguing Avery should not even be allowed to raise an evidence-planting defense. In the end, the judge allowed the defense to proceed, but restricted it for trial purposes to Lenk and Colborn, two of the primary evidence technicians who interviewed Avery on separate occasions in early November 2005.

"In most of these evidence-planting cases, it's one or two guys," Buting recently told USA TODAY NETWORK-Wisconsin. "The whole idea that it would need to take almost the whole department is not borne out by the history of planting in other law enforcement cases that have been documented."

Between 2005 and 2012, there were at least 169 cases of police officials around the country who were charged with evidence tampering crimes, said Phillip Stinson, a Bowling Green State University criminal justice professor. At least 34 involved violent crimes such as homicides.

"It's not a huge number," Stinson said, "I believe we're dealing with rare exceptions, but that being said, I always wonder if we're just dealing with the tip of the iceberg."

This past June, an ex-Kenosha officer was given probation after pleading guilty to felony misconduct in office as part of an evidence-planting scandal. In 2014, officer Kyle Baars, a three-year officer, planted a murder suspect's identification card and a .22-caliber bullet inside of a backpack that Baars found inside the suspect's house during a police search. Baars kept quiet about his misconduct for several months before confessing to a detective.

RELATED: Evidence planting claims not limited to Steven Avery

FULL COVERAGE: Read all our stories about Steven Avery

Avery's post-conviction lawyer, Kathleen Zellner, has identified Lenk and Colborn in court documents as being her main targets of suspected police corruption. Zellner won't say whether she is also exploring others as well.

"Show me the evidence he was framed. There is not going to be any. It didn't happen," Sheriff Rob Hermann told USA TODAY NETWORK-Wisconsin after last December's release of the docu-series "Making A Murderer." "I don't know why anybody in law enforcement would want to get him, that makes no sense."

Zellner faces an uphill climb in connecting the dots of her evidence-planting theory, Stinson said.

"It's already 11 years," he said. "These are cases that are damn near impossible to win when you're dealing with post-conviction appeals. It's very difficult. But that said, these kinds of proceedings have unearthed a number of examples of a police conspiracy to set somebody up."

On Dec. 4, Zellner energized her more than 170,000 social media followers by tweeting that the cops planted evidence against Avery — just not in the way that Avery's trial lawyers theorized.

USA TODAY NETWORK-Wisconsin has revisited details behind the evidence-planting theory raised at Avery's trial, along with Zellner's court transcripts. She is now in the process of having nine pieces of evidence retested by independent scientists.

If Zellner uncovers proof of evidence-fabricating, it's more likely that a small number of people were engaged in misconduct rather than dozens.

USA TODAY NETWORK-Wisconsin found there was a tendency of Manitowoc and Calumet counties to selectively reprocess a room, a garage or a vehicle — even after that location underwent an extensive evidence search previously.

It became a recurring pattern in the murder cases against Avery and his nephew, Brendan Dassey, that when a follow-up search was ordered, new forensic clues would emerge.

RAV4, AVERY'S BLOOD

Summary: Discovered on Saturday, Nov. 5, 2005, by volunteer searcher Pam Sturm in the corner of Avery's Salvage Yard. The day before, then-Calumet County Sheriff Jerry Pagel and investigator Wendy Baldwin flew over the salvage yard and nearby quarries but did not locate the vehicle at Avery's, reports show.

Working theory: Manitowoc County found the Halbach vehicle two days earlier, and moved it to Avery's property late at night on Nov. 4.

"On Nov. 3, 2005, Officer Colborn discovered the victim's vehicle and called dispatch, on a personal line, to confirm the victim's license plate number," Zellner wrote in court filings. "On Nov. 3, 2005, according to the Manitowoc County Sheriff's Department reports, Ms. Halbach's vehicle was seized."

Zellner contends that someone else, perhaps Lenk, was with Colborn at the time he called dispatch. In the audio recording of Colborn's call, a man's voice can be heard shouting in the distance, "the car's here!"

When Sturm found the vehicle, the license plates were gone. Doors were apparently locked. The car battery was disconnected. If cops were planting blood and putting the vehicle at Avery's, they would take no chances that one of the Averys would recognize it and try to move it.

"Mr. Avery contends that the blood evidence was planted in Ms. Halbach's car, by law enforcement, prior to the discovery of the vehicle on the Avery property on Nov. 5, 2005, two days prior to it being planted on the Avery's property," Zellner wrote in court documents. "Either Officer Lenk and/or Officer Colborn were connected to the discovery of each item of planted evidence."

SPARE KEY

Summary: Calumet County Lt. Brett Bowe requested that deputy Dan Kucharski, Colborn and Lenk return to Avery's trailer to re-search it for evidence — even though the trailer had undergone a 2½-hour search involving Colborn, Lenk, Remiker and Calumet Sgt. Bill Tyson three days earlier. Kucharski's reports indicate they entered the trailer at 8:25 a.m. His report doesn't say what time they found the key. "We all believe the key was dislodged from the back of the cabinet as we were tipping and banging the magazines and binder in and out of the cabinet," Lenk wrote in his reports. From there, the key was sent to the state crime lab. There, analyst Sherry Culhane revealed it contained a full DNA profile for Avery. Prior to the key's discovery on the fourth day of the massive police presence of Avery salvage, authorities had found no forensic evidence inside Avery's trailer to tie him directly to Halbach's disappearance.

Working theory: Manitowoc and Calumet deputies were under pressure to bring the Avery murder investigation to a quick close, after the previous three days of searching at Avery's property were mostly a failure. The key that was trumpeted as crucial evidence, however, did not contain Halbach's DNA. In fact, Halbach's full set of keys, including ones for her Green Bay photo studio and her farmhouse near Hilbert, have never been found. Given the possibility that the spare key was planted, it may have come from Halbach's farmhouse. Otherwise, it could have been found somewhere in the RAV4.

LICENSE PLATES

Summary: The entire salvage yard — roughly 4,000 vehicles — was searched for signs of Halbach during daylight on Sunday, Nov. 6. No significant clues were found. Early the next morning, Colborn and Lenk went back and rechecked a number of vehicles that were missed the day before. The following day, the command staff ordered that the massive junkyard be rechecked by the team of volunteer firefighters and Wisconsin state troopers. This time, a Brillion volunteer firefighter alerted others to Halbach's crumpled license plates in the backseat of an old station wagon.

Working theory:Colborn or Lenk put the plates into the abandoned station wagon that was missing its windows and was within a short walk from Avery's red trailer. "The license plates were removed from the victim's RAV4 and put into another vehicle at the time the victim's vehicle was deposited on the Avery property," Zellner's court filings show. In August, Zellner informed the court that she intends to obtain the fingerprint comparisons of Lenk and Colborn. At Avery's murder trial, special prosecutor Ken Kratz downplayed the fact that none of the eight fingerprints found inside and outside of Halbach's RAV4 came from Avery. "If the unidentified fingerprints on the victim's vehicle match either Officer Colborn or Officer Lenk, it would be significant evidence of their involvement in moving the victim's vehicle onto the Avery property."

CHARRED BONES

Summary:About five hours after the spare key and license plates were recovered as evidence, Manitowoc sheriff's Sgt. Jason Jost reportedly found a couple of charred human bones near Avery's burn pile pit. According to his report, Jost had a hunch that the burn pit area warranted further scrutiny. "I felt this area, if not already looked at, should be checked for any type of evidence," Jost's report showed. Jost's report indicates that he also was near the burn pile pit the previous day.

Working theory:The decision to plant charred human bones was in the works prior to Jost's discovery on Nov. 8. "Mr. Avery contends that the victim's key and bones were planted on Nov. 7, 2005, and were discovered on Nov. 8, 2005," Zellner stated. "Most of Ms. Halbach's bones and 29 of her teeth were not found in Mr. Avery's burn pit." In addition, Tom Sturdivant, an arson investigator with the Wisconsin Division of Criminal Investigation in Wausau, would lead efforts to excavate the burn pile pit. Sturdivant hadn't been at Avery's during the previous three days. Jost and Sturdivant did not photograph or videotape the bones, even though this marked the biggest evidence discovery of the weeklong criminal investigation.

The bones may have originated from one of the nearby quarries behind Avery's, where other burnt debris including charred pelvic bones, were being recovered by Calumet deputies and state investigators. In addition, Lenk, Colborn, Remiker and Kucharski confiscated four burn barrels from Avery's sister's yard on Nov. 6. At least one of those barrels contained charred human bones, yet none of the evidence technicians took any photographs or videotape showing the contents inside the barrels. The barrels were put into an enclosed trailer that Manitowoc sheriff's deputy George Tackes drove to the Calumet County Sheriff's Department for processing there.

BULLET FRAGMENT

Summary:When Dassey, Avery's 16-year-old nephew, implicated himself as an accomplice, authorities had no forensic evidence indicating that Halbach's body was riddled with bullets inside Avery's garage. During an interview with Dassey, DCI Special Agent Tom Fassbender suggested Halbach was shot inside the garage. On March 1 and 2, 2006, Lenk and Remiker returned to Avery's property. This time, additional bullet fragments were discovered in the garage. When Lenk, Remiker, Colborn and Kucharski searched it in November 2005, the bullet fragments were either overlooked or were never there. Lenk testified he did not go inside the garage in March 2006. "I came back to see if they needed any, uh, food, any assistance with supplies, see if I could help out," Lenk testified. Sherry Culhane of the state crime lab advised Calumet County that "Teresa Halbach is the source of the DNA present on the bullet fragment."

Working theory: Lenk or Remiker were involved in planting the ammunition that was recovered in March 2006. Lenk ran his agency's evidence storage unit and Remiker was his direct subordinate. Both men drove together to Avery's on Nov. 4, 2005, to question Avery about Halbach's disappearance. After Halbach's vehicle was found, Remiker offered to take charge of the evidence collection efforts at Avery's property with Colborn and Lenk, even though Lenk and Colborn had recently testified as part of Avery's $36 million wrongful conviction lawsuit against his county and their former boss, ex-sheriff Tom Kocourek. "I offered (Calumet County) the services of myself and Lt. Lenk and Sgt. Colborn to give them a hand," Remiker testified.

HOOD LATCH SWAB

Summary:Six swabs were collected by Calumet County deputy Jeremy Hawkins and Sgt. Bill Tyson from Halbach's RAV4 on April 3, 2006. The decision to reprocess the victim's vehicle occurred about a month after special prosecutor Ken Kratz's sensational pretrial press conference claiming Avery was drenched with sweat inside his bedroom while restraining Halbach's naked body before stabbing her with a butcher knife and shooting her. The RAV4 originally underwent a rigorous forensic examination on Nov. 7, 2005, at the state crime in Madison. By the time Calumet County decided to check it again, it was under the sheriff's custody at a storage garage facility in Chilton. In May 2006, Culhane contacted Calumet County to report an important breakthrough to bolster the prosecution. "It is the opinion of the analyst, to a reasonable degree of scientific certainty, that Steven Avery is the source of the DNA present from the swabbings of the hood latch," she advised.

Working theory: Someone in law enforcement tampered with evidence swabs that contained Avery's DNA. Trial testimony revealed the Manitowoc County Sheriff's Department had retained some older specimens of Avery, including DNA buccal swabs, hair samples and fingernail clippings. The state crime lab sent the Avery DNA samples back to Manitowoc County in 2003, even though that agency may have framed Avery for a brutal rape that unjustly sent him to prison for 18 years. In addition, Remiker and Lenk were regular visitors to their evidence storage room.

Prior to deciding to reprocess the RAV4, Calumet encountered a number of setbacks earlier that day, dampening Kratz's theory of how the murder unfolded. When Calumet deputies examined Avery's headboard, they saw no "striations ... consistent with that of having handcuffs or leg irons secured to the spindles of the headboard," their reports show. Next, presumptive blood tests were done on the stains from Avery's mattress, "all of which turned up negative for the presence of blood." Later that evening, Tyson and Hawkins were dispatched to the storage garage. They got six more swabs from the RAV4, including the hood latch. The swabs were then put into their agency's evidence room for holding prior to being tested by Culhane.

John Ferak of USA TODAY NETWORK-Wisconsin: 920-993-7115 or jferak@gannett.com; on Twitter @johnferak