The Oakland County Child Killer 3

In 2005, an unidentified man, who would later emerge to become a common figure in the case and has been referred to by the alias of "Jeff", was reminded of a relationship he had in 1977 with an acquaintance. In an interview given to Oakland County investigators in 2010, Jeff informed them of atypical observations and actions while driving and conversing with the acquaintance, such as taking him to buildings where satanic rituals were allegedly performed. The acquaintance navigated through lesser-known routes associated with the case with ease. The acquaintance also spoke of details written in "Allen's" letter. Jeff requested information about the "Allen" letter to help confirm his suspicions, but was denied.

In 2010, Jeff gave a recorded interview to Oakland County investigators and Prosecutor Jessica Cooper to present evidence pertaining to the investigation. Jeff claimed to have tried to approach Cooper with his findings and to convince her to place the case under the jurisdiction of the Department of Justice. The department was already involved through the FBI and through resources such as the ViCAP database. Cooper dismissed his suggestions and, as there was no new evidence presented, his request to inspect the "Allen" letter was denied. Cooper described the interview as "a rambling statement outlining a theory that the Oakland County Child Killer abductions and murders were related to pagan holidays, the lunar calendar, and Wiccan rituals".

Jeff proceeded to correspond with Deborah Jarvis, mother of victim Kristine Mihelich, and investigative journalists such as Bill Proctor and Heather Catallo in 2010. He claimed that he was among a team of a dozen investigators involved with the case and could identify the perpetrator of the crimes, but refused to indicate which law enforcement division he worked for. Jeff claimed to have invested 10,000 hours into the investigation over several years, but was reluctant to release his results as he doubted the competence of Wayne and Oakland County investigators. In a press release email, Jeff indicated possible meddling by Cooper and other reasons as to why he had not made his investigation public. According to Paul Hughes, an attorney representing Jarvis, Jeff's investigation discovered the murderer. However, according to Hughes, Jeff refused to identify the culprit unless the authorities divulged crucial information which Jeff requested during the initial interviews in 2010. Jeff wanted to positively confirm the identity of his suspect using the police evidence before proceeding further.

In 2012, Jeff presented his findings to a select group of Detroit journalists on Hughes' cell phone. To preserve his anonymity he insisted that his phone interview with Hughes not be recorded. He theorized that the killers were conducting Wiccan human sacrifice rituals coinciding with pagan celebrations or the lunar calendar. According to Jeff, there was a total of approximately 11–16 victims, significantly more than the four officially confirmed victims. He claimed his team found a number of similarities among the cases that were highly unlikely to be purely coincidental.

Based on this information, Hughes attempted a lawsuit against the Oakland County authorities for $100 million, citing mishandling of the investigation and demanding Cooper's resignation. The lawsuit alleged a cover-up conspiracy and obstruction. Hughes' website solicited donations, and offered a copy of Jeff's report for a donation of $1,500. The families of the victims, as well as Cooper, claimed that Hughes and Jeff were attempting to profit on their distress. The case was dismissed in March 2012 for lack of evidence.

In February 2019, the Investigation Discovery channel aired a two-part, four-hour documentary about the killings. At this same time, WXYZ-TV investigative reporter Heather Catallo announced that a key suspect, convicted child sex offender Arch Edward Sloan, had failed a polygraph test when he was interviewed by the Oakland County Child Killer Task Force in 2010 and 2012. Back in 2012 new DNA technology found that Sloan's car contained hair with the same mitochondrial profile as evidence found on the victims; however, it is not Sloan's.