A former lead investigator in the still-unsolved JonBenet Ramsey murder case has come out with a book explaining his theory that there never was an intruder.

James Kolar claims in his book, "Foreign Faction: Who Really Kidnapped JonBenet?" that the evidence raised questions about the intruder theory that eventually led to JonBenet's family being cleared.

"I was kind of discouraged they didn't want to pursue things I thought should be looked at," Kolar said. "I was kind of discouraged the work I had done was not being received well," Kolar told the Daily Camera.

The title of Kolar's book correlates with the ransom note found in the Ramsey's home which claimed to be written by a "small foreign faction."

Kolar says he'd been hoping the case would have been solved by now and that his book could have been written from that vantage point. The former detective had access to 60,000 pages of evidence, including crime-scene video and photos, interviews with individuals related to the case and forensic reports.

Among the contradicting evidence Kolar points out in his book are fully intact cobwebs stretching over the window the intruder allegedly entered, more DNA evidence found at the crime scene including DNA on the garrote cord used to strangle the young girl.

In his book, Kolar also writes about a child's toy that was found that may have been responsible for some of the abrasions on JonBenet's body, rather than a stun gun which had been considered a possible source of the injuries to her back, according to The Daily Beast.

"By the time I parted company with the D.A.'s office, I was convinced that there was no significant possibility that an intruder had been involved in the death of JonBenet," Kolar writes in his book.

Read a detailed new report on the book at The Daily Beast.

On Dec. 26, 1996, 6-year-old JonBenet was found bludgeoned and strangled to death in the basement of her family home. A ransom note from an anonymous group of individuals "that represent a foreign faction" asking for $118,000 in exchange for the safe return of JonBenet was found just hours before, but no call ever came from a kidnapper and it was never linked to a murderer. See the full text of the ransom note originally published by Vanity Fair magazine and republished by The Daily Camera, here.

John and Patsy Ramsey, JonBenet's parents were prime suspects for years and repeatedly appeared on news channels defending their innocence and demanding justice for the murder of their young daughter. The entire Ramsey family was cleared of any involvement in the murder of JonBenet back in 2008, thanks to then newly discovered DNA evidence, according to 9News. Patsy Ramsey, JonBenet's mother, died 2 years earlier in 2006 of ovarian cancer, tragically, she was still considered a possible suspect when she died.

Beginning in 2010, investigators reopened the case and launched a fresh round of interviews with witnesses that could provide more insight into the murder, according to ABC News, but nothing fruitful came of those interviews.

The DNA evidence still points to an "unexplained third party" that serves as a vague lead for authorities still pursuing the case, TIME magazine reported.

According to 7News, Boulder police have tested more than 150 DNA samples and investigated nearly the same amount of potential suspects in their ongoing investigation, but none have ever been linked to the crime.

After all these years, Boulder police have received thousands of tips about her murder and still receive several monthly. Boulder District Attorney Stan Garnett said in 2010 that he personally gets five or more tips each month, according to Fox31. The ones that have potential are passed along to Boulder police's Major Case Unit. There have been plenty of false leads as well, including most famously Mark Karr -- who bizarrely admitted to being with JonBenet the night of her death, but DNA evidence later cleared him of any wrongdoing in this case, MSNBC reported. Craig Silverman, talk radio legal analyst on 630 KHOW that has covered the unsolved murder since it first broke, spoke to KDVR about the public's interest in the case back in 2010:

It's an enduring, epic mystery. Everybody would like to know who killed little JonBenet.

Silverman went on to say on his Huffington Post blog, "This JonBenet murder mystery has never been lacking for clues. There are too many clues. It is putting all the puzzle pieces together that matters."

It remains one of the most notorious murders in U.S. history and a decade and a half later there is still no justice for JonBenet who would be nearing her 22nd birthday if she were alive today.

For a timeline of the events of the unsolved murder case during its peak years in the 1990s check out the Daily Camera's chronological summary of the major events from Dec. 1996 to 1999.

Look at photos of the JonBenet Ramsey case below and watch police footage from the Ramsey's basement taken hours after JonBenet's body was found, above, via The Daily Beast.

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  • JonBenet Patricia Ramsey winning a beauty pageant at 1996 America's Royale Little Miss National Beauty contests.

  • **FILE** This is an undated photo of 6-year-old JonBenet Ramsey, who was found dead in the basement of her family's home in Boulder, Colo., Thursday, Dec. 26, 1996. (AP Photo/Boulder Police Department, FILE)

  • A Boulder Police detective walks to the home of John and Patricia Ramsey in Boulder, Colo., on Friday, Jan. 3, 1997, as investigators sifted through evidence in the home in which the couple's 6-year-old daughter was found murdered on Dec. 26, 1996. A decade after the Christmastime slaying of JonBenet Ramsey, two aspects of the case endure: the public's endless fascination with the murder of the 6-year-old beauty contestant, and a sense the notorious crime may never be solved.

  • This is the home of John and Patricia Ramsey in Boulder, Colo., seen Jan. 3, 1997, as investigators sifted through evidence in the home in which the couple's 6-year-old daughter JonBenet Ramsey was found murdered on Dec. 26, 1996. (AP Photo/David Zalubowski)

  • ** FILE ** A Boulder Police Department detective leaves the home of John and Patricia Ramsey in this Jan. 3, 1997 file photo in Boulder, Colo. A man arrested in Thailand is being held in connection with the slaying of JonBenet Ramsey, U.S. officials said Wednesday Aug. 16, 2006. Federal officials familiar with the case, who spoke on condition of anonymity, said the man was already being held in Bangkok on unrelated sex charges. (AP Photo/David Zalubowski, File)

  • Shrouded by trees near, an unidentified investigator uses a tape measure on the Ramsey family home early Tuesday, July 1, 1997, while gathering information to construct an architectural model of the 6,000-square-foot, Tudor-style home in which JonBenet Ramsey was murdered more than six months ago in Boulder, Colo. Boulder police, along with district attorney investigators and members of the Colorado Bureau of Investigation, have been scruntinizing the home since Monday and may be in the home for up to a week. (AP Photo/David Zalubowski)

  • Flowers rest in the snow outside the home of JonBenet Ramsey on the one-year anniversary of her murder, Friday, Dec. 26, 1997, in Boulder, Colo. A candlelight vigil was scheduled for later in the evening. (AP Photo/Michael S. Green)

  • FILE--Boulder Sheriff's Department cadets V. Montez, left, and E. Hill are shown standing guard in this Dec. 27, 1996 file photo outside the home in Boulder, Colo. in which 6-year-old JonBenet Ramsey was found dead on December 26. (AP Photo/David Zalubowski, File)

  • Patsy Ramsey and her husband, John, give a news conference in Atlanta on May 24, 2000 regarding their polygraph examinations for the murder of their daughter, JonBenet. The test results said the couple were not "attempting deception" when they denied killing their 6-year-old daughter. Patsy Ramsey has died of ovarian cancer, KCNC TV reported Saturday, June 24, 2006.

  • In this Aug. 29, 2000 file photo, Patsy Ramsey speaks as her husband John Ramsey listens during a short news conference in Atlanta. Prosecutors say new DNA tests have cleared JonBenet Ramsey's family in the 1996 killing of the 6-year-old beauty queen. Boulder County District Attorney Mary Lacy said Wednesday, July 9, 2008, that the tests point to an "unexplained third party." Lacy apologized to the family, saying, "To the extent that this office has added to the distress suffered by the Ramsey family at any time or to any degree, I offer my deepest apology."

  • **FILE** In this Aug. 3, 2004 file photo John and Patsy Ramsey, parents of slain beauty queen JonBenet Ramsey, are shown during the election for Michigan's 105th District at his campaign headquarters in Charlevoix, Mich. When Boulder County district attorney candidate Stan Garnett checked his cell phone after a long flight last week, he had dozens of messages asking his opinion about the latest DNA tests in the JonBenet Ramsey case. (AP Photo/Carlos Osorio, File)

  • Members of the grand jury investigating the murder of JonBonet Ramsey leave the Justice Center in Boulder, Colo., Wednesday, Oct. 13, 1999. Nearly three years after the slaying of Ramsey, the grand jury decided Wednesday there isn't enough evidence to charge anyone in the 6-year-old beauty queen's strangulation. Grand jurors from left are Martin Pierce, Loretta Resnikoff, Jonathan Webb, Martin Kordas Jr., Josephine Hampton, foreman James Plese, Barbara McGrath-Arnold and Susan LeFever.

  • Exterior view of a courthouse is shown in Boulder, Colo., Monday, Aug. 21, 2006. John Mark Karr, a school teacher who cryptically claimed to have been present when JonBenet Ramsey was killed in 1996, may have a hearing in this courthouse. Karr arrived in Los Angeles late Sunday after a flight from Thailand, where he was arrested last week. He faces legal proceedings in California before he is sent to Boulder. (AP Photo/Paul Sakuma)

  • New York attorney Darnay Hoffman holds a 19-page affidavit and complaint during a news conference Tuesday, Nov. 18, 1997, in New York. Contending the JonBenet Ramsey case has been mishandled, Hoffman is going to court to challenge the actions of the Boulder County district attorney. Hoffman, who is also the attorney for Bernhard Goetz, said he will take advantage of a Colorado law that allows private citizens to question the actions of prosecutors. (AP Photo/Michael Schmelling)

  • American John Mark Karr, center, is taken to a police news conference by Thai plainclothes police officers at Immigration office in Bangkok, Thailand Thursday, Aug. 17, 2006. In 2006 Karr falsely confessed to murdering Jon Benet Ramsey.

  • An assistant at a Thai dermatology clinic displays a computer image of John Mark Karr, a suspect in the murder of child beauty queen JonBenet Ramsey, that was taken in March in Bangkok and displayed on Monday, Aug. 21, 2006 by a dermatologist whom Karr consulted. The dermatologist, Dr. Setthakarn Attakonpan, said Karr had four appointments with him and his assistants to remove his facial hair in preparation for what Karr told him would be a sex-change operation. He said the marks on Karr's face were to show where hair should be removed by laser surgery.(AP Photo/Sakchai Lalit)

  • Murder suspect John Mark Karr listens during an extradition hearing in Los Angeles Superior Court Tuesday, Aug. 22, 2006. Karr waived extradition Tuesday and will be returned to Boulder, Colo., where he is charged with murdering JonBenet Ramsey a decade ago. (AP Photo/Mario Anzuoni, Pool)

  • Patsy Ramsey's sister Paulette Davis brushes off the grave of JonBenet Ramsey at the St. James Episcopal Cemetery in Marietta, Ga., Thursday, Aug. 17, 2006. A man arrested in Thailand is being held in connection with the slaying of JonBenet Ramsey, U.S. officials said Wednesday, Aug. 16, 2006. The girl was found beaten and strangled in the basement of the family's home in Boulder, Colo., on Dec. 26, 1996. (AP Photo/Wilford A. Harewood)