In November 2013, Joanna Dennehy pleaded guilty to all three murders and two further attempted murders.Dennehy's sister Maria was unsurprised by the guilty plea and said: "I think she did that to control the situation. She likes people to know she's the boss."
Dennehy has been held at HM Prison Bronzefield where Rosemary West is being held. Assessing psychiatrists later claimed Dennehy has a psychopathic personality structure due to a co-morbid borderline personality disorder and antisocial personality disorder diagnosis.
Two men, Gary Richards (known as Gary Stretch), 47, and Leslie Layton, 36, stood trial charged with a range of crimes assisting Dennehy. Neither agreed to enter the witness box, give sworn evidence or face cross-examination.The jury began considering their verdict on 4 February 2014. On 10 February Richards was found guilty of attempted murder. Layton was found guilty of perverting the course of justice. On 12 February Layton and Richards were convicted of all other charges.
On 28 February 2014 At the Old Bailey Joanna Dennehy was sentenced to life imprisonment, The trial judge, Mr Justice Spencer, recommended that she should never be released. He said that this was justified due to the premeditation of each murder, Spencer said further that Dennehy was sadomasochistic, and lacked the normal range of human emotions. Dennehy is believed to be one of just three women in the United Kingdom to be told that her life sentence should mean life. The other two confirmed cases are Myra Hindley (now deceased) and Rosemary West.Gary 'Stretch' Richards was also sentenced at the Old Bailey alongside Dennehy to life imprisonment with a recommended minimum term of 19 years. Leslie Layton was sentenced to a total of 14 years and Robert Moore, 55, who admitted assisting an offender received a three-year prison sentence.
"Timeline of police Operation Darcy into murders of three Peterborough men from 2013" from the "Peterborough Telegraph" newspaper - lists a timeline of key dates, locations and events between March 2013 until February 2014 tracing the murders of Kevin Lee, Lucasz Slaboszewski and John Chapman in Peterborough and subsequent court case.
Kevin Lee was a property developer, landlord of Joanna Dennehy and her lover. He was killed on 29 March, and his body found the next day near Newborough. Dennehy dressed Lee's body in a black sequined dress before dumping his corpse.
Lukasz Slaboszewski and John Chapman were housemates of Dennehy.Slaboszewski was killed between 19 and 29 March and Chapman on 29 March. Slaboszewski and Chapman were both found on 3 April near Thorney with stab wounds.
After the killings Dennehy and Richards drove to Hereford where she stabbed two random men, both of whom survived.