[1] The victims of Bible John were all brunettes between the ages of 25 and 32, all of whom met their murderer at the Barrowland Ballroom, a dance hall and music venue in the city.

On 23 February 1968, the naked body of 25-year-old auxiliary nurse Patricia Docker was discovered in the doorway of a lock-up garage in the alleyway behind 27 Carmichael Place, Battlefield, Glasgow.

[14][6] Extensive door-to-door inquiries in the area produced a witness who recalled possibly hearing a female twice briefly shout "Let me go" the previous evening.

[20][21][22] A postmortem conducted by Gilbert Forbes at the University of Glasgow Medical School confirmed that the cause of death had been strangulation, and that Docker's body bore no clear evidence of sexual assault.

[32][18][5][6] The general gradient of Carmichael Place would have allowed a car to enter the location quietly and without the driver using the engine, and the use of a vehicle would have enabled the killer to discreetly take the missing clothing and jewellery from the crime scene without being seen.

A few weeks into the investigation, an anonymous letter was posted from the north of England by a woman police believed may have been in Glasgow city centre on the night of Docker's death and who may have known the identity of the killer.

Later the same day, she began hearing local rumours that young children had been seen leaving a derelict tenement building in MacKeith Street discussing a body in the premises.

[20][7] Investigators were unable to conclusively determine whether MacDonald had engaged in sexual activity—consensual or otherwise—prior to her murder, and although her other clothing was somewhat disrupted, the two pairs of pants she was wearing appeared to have been undisturbed.

[43][n 2] Police inquiries into MacDonald's movements on the night of her murder produced several eyewitnesses who were able to accurately describe the man in whose company she had been seen at the Barrowland.

Door-to-door inquiries on MacKeith Street also produced a woman who remembered hearing female screams on the evening of MacDonald's murder, but she could not recall the precise time.

[25] For the first time in a Scottish murder hunt, a composite drawing of the man MacDonald had last been seen alive with was given to the press, being widely distributed via both newspapers and upon television throughout Scotland in efforts to identify the suspect.

[7][55] The suspect was described by Puttock's sister Jean Langford as being a tall, slim, and well-dressed young man wearing a well-cut brown Reid and Taylor brand suit,[56] with reddish, sandy or fair hair rounded neatly at the back.

[29][65][5] This incident caused a sudden change in the suspect's previously polite demeanour; he demanded to see the manager, with whom he argued aggressively, and asked to know who the local MP was.

[77][5] Langford also recalled his mentioning he had at one stage worked in a laboratory,[82] that his family had a caravan in Irvine, and that although he played golf badly, his cousin had recently scored a hole in one.

[85][87] The taxi driver was unfamiliar with the route and had made some wrong turns in the last part of the journey,causing Puttock had become frustrated and ask him to stop on Earl Street.

[n 5] It was initially believed that the man may have used the nearby Govan ferry to cross the River Clyde to the south of the city, but the ferrymen working that night could not remember such an individual.

[56] The police also produced an artist's impression portrait, created by Lennox Patterson, Registrar of the Glasgow School of Art, based on the recollections of Puttock's sister.

[13] Others speculated that he may have simply moved away from the Glasgow district, or murdered whenever in the vicinity;[102] this possibility prompted police to circulate multiple copies of the composite drawing at all British Army, Navy, and Air Force bases in the United Kingdom, Europe, and the Middle and Far East; this line of inquiry failed to produce any significant leads.

[103] Les Brown, who worked on the Bible John case as a junior detective, claimed in 2005 that he had identified a likely suspect at the time but that he was dismissed simply because he did not have notably overlapping front teeth.

[112] One of these women, Hannah Martin, claimed that she had been assaulted and raped by Bible John and had subsequently given birth to his child in January 1970; a daughter she initially named Isobel.

[118][119][n 9] The results of the testing conducted proved inconclusive, with then-Lord Advocate Lord Mackay stating insufficient evidence[120] existed to link McInnes with the murder of Helen Puttock.

He had lived in Shettleston in Glasgow in the late 1960s; he then relocated to England in August 1969 (before the final two murders committed by Bible John) after marrying his first wife, who he had met at the Barrowland Ballroom in 1968.

[129] In addition, all three of Tobin's former wives have given accounts of being repeatedly imprisoned, throttled, beaten, and raped by him, and each has stated he had been driven to extreme physical violence by the female menstrual cycle (a factor long suspected by investigators as being the perpetrator's motive behind the murders).

This information, alongside other circumstantial evidence, led Wilson to state: "I didn't set out to prove Tobin was Bible John, but I would stake my professional reputation on it.

[145][16] Alex–who claimed to have last seen Docker at her home in October 1967 when the two had met to discuss divorce[16][6]—was considered by police to have had a possible motive to kill his estranged wife.

[16][n 13] Jemima MacDonald had also recently separated from her husband at the time of her murder, and had likewise moved back to Glasgow the year prior to her death.

[149] Contemporary police reports indicate MacDonald had visited the Barrowland for three successive nights in the week prior to her murder, and that she was "in receipt of public funds, plus maintenance from the fathers of her children".

[158] In 2004, police announced their intentions to genetically test several men in a further attempt to identify the perpetrator, with all concerned being requested to submit blood samples.

Langford had given police the description used to form the second composite drawing created of the suspect, which remains the most significant clue as to the perpetrator's physical appearance.

Presented by journalist Audrey Gillan and titled Bible John: Creation of a Serial Killer, this series was broadcast between 29 September and 7 December 2022.