Katrin Mueller-Johnson is Associate Professor of Criminology and a Research Fellow at Green Templeton College.
Previously she was a lecturer and senior lecturer at the Institute of Criminology at the University of Cambridge. She holds a PhD  in Human Development from Cornell University, a MSt in Legal Research from the Centre of Social Legal Studies, University of Oxford, and a Dipl. Psych. Degree in Psychology from the Free University of Berlin.

Her research interests are centred around victimisation, investigative interviewing and police as well as legal decision-making.

Within the area of victimisation her main concentration is on sexual offences, such as in child sexual abuse or rape. Her current research focuses on vicarious victimisation of police officers and police staff in the context of child abuse investigations. Her research into investigative interviewing is connected to this interest in sexual victimisation as in sexual offences there is often little evidence apart from the victim statement and thus the victim's testimony is of crucial importance. Dr Mueller-Johnson studies police interviewing of vulnerable witnesses, such as the investigative interviewing of children, older adults, or persons with disabilities. One major area of this research is on ways to improve the quality of police interviews. Her research on decision-making in the criminal justice context spans police as well as jury and judges' decision-making. Here projects have looked into differences in how potential jurors interpret the phrase “beyond reasonable doubt”, and into judges’ assessments of witness credibility.

Her work has been funded by the AHRC, ESRC, British Academy, Newton Trust, Optimus Foundation and Department of Justice for Northern Ireland. She has collaborated with UK and international police forces.


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  • Z. McKee, K Mueller-Johnson and H. Strang, 'Impact of a training programme on police attitudes towards victims of rape: a randomised controlled trial.' (2020) 4 Cambridge Journal of Evidence Based Policing 39
    [Open Access]
    Abstract RESEARCH QUESTION: Does an in-service training programme designed to address the attitudes of student officers, uniformed response officers and specialist rape crime investigators towards victims of rape change their perspective on adult victims, both male and female, who report rape offences? DATA: Police officers from four separate policing roles completed questionnaires designed to measure their attitudes towards victims of rape. The questions were already validated and used four specific subscales: ‘Asked for it’, ‘Didn’t mean to’, ‘It wasn’t really rape’ and ‘S/he lied’. Two questionnaires, one focused on male victims and one on females, were administered at different points in time. METHOD: This randomised controlled trial used a block design, randomly assigning eligible police officers to treatment and control conditions within each of four groups. Participants were grouped as rape detectives (N = 40), uniformed response officers in urban areas (N = 50); uniformed response officers in rural areas (N = 50) and student officers (N = 53). Officers in the treatment condition undertook a bespoke training programme, based on an online College of Policing e-learning programme, enhanced with audio and video content, discussion groups and short online webinar sessions delivered by a psychologist specialising in sexual offending. Both groups were surveyed before and after the treatment group was trained. FINDINGS: The training programme resulted in positive attitude changes towards male and female rape victims when responses are combined across all four police groups (but not within all groups separately) compared with the attitudes of those who did not undertake the training. Effects were found for both levels of rape myth acceptance and assessment of victim credibility. The effect was largest for the subscales ‘S/he lied’ and ‘it wasn’t really rape’. Training had more effect on attitudes towards female victims than towards males and more effect on uniformed response officers than on other categories of officers. CONCLUSION: The use of this mixed online webinar and in-person discussion group training delivery was effective in changing attitudes towards rape victims on issues relating to the treatment of people who report being raped.
  • A.M. Gasso, K Mueller-Johnson, I. Montiel and J.R. Agustina, 'Sexting and Mental Health among a Spanish College Sample: an exploratory analysis' (2020) 13 International Journal of Cyber Criminology 534
    DOI: doi:10.5281/zenodo.3709214
    ABSTRACT: Recent research on sexting suggests it could be related to mental health, but so far studies have often used simple and not clinically validated measures of mental health. Specific aims of this study were: 1) to analyze the lifetime prevalence of sexting behaviors among a Spanish College Sample by gender, and 2) to examine the psychopathological profile of those students who engaged in sexting. METHOD: The sample consisted of 120 Spanish college students (75% female, 22.1 mean age) who took part in an online survey about their engagement in sexting behaviors and psychopathological symptomatology, measured by LSB-50. RESULTS: Out of the sample, 42% of participants engaged in active sexting behaviors, 58% in passive sexting, and 31% of participants had both received content and sent content. Furthermore, 41.1% of the sample showed depressive symptoms, whilst 52.7% reported anxiety symptoms, and sexters were 2.98 times more likely to be depressed, 2.52 times more likely to have anxiety, and 2.63 times more likely to show global psychopathology than non-sexters. CONCLUSIONS: Sexting is highly prevalent amongst Spanish college students, and those people who engage in sexting have higher ratios of mental health issues.
  • A.M. Gasso, K Mueller-Johnson and I. Montiel, 'Sexting, Online Sexual Victimization,and Psychopathology Correlates by Sex: Depression, Anxiety, and Global Psychopathology' (2020) 17 International Journal of Environmental Research and Public Health 1018
    [Open Access]
    ABSTRACT: Recent research on sexting highlighted a relationship between this new technology-mediated behavior and psychopathology correlates, although up to date results are mixed, and so far, studies have often used simple and not clinically validated measures of mental health. This study aimed to investigate sexting behaviors, online sexual victimization, and related mental health correlates using clinically validated measures for global psychopathology, anxiety, and depression; and doing so separately for men and women. The sample consisted of 1370 Spanish college students (73.6% female; 21.4 mean age; SD = 4.85) who took part in an online survey about their engagement in sexting behaviors, online sexual victimization behaviors, and psychopathological symptomatology, measured by a sexting scale and the Listado de Síntomas Breve (brief symptom checklist) (LSB-50), respectively. Out of our total sample, 37.1% of participants had created and sent their own sexual content (active sexting), 60.3% had received sexual content (passive sexting), and 35.5% had both sent and received sexual content, with significant differences between male and female engagement in passive sexting. No differences were found between men and women in the prevalence of their victimization by nonconsensual dissemination of sexual content; however, women were more pressured and threatened into sexting than men. Sex differences in psychopathology were found only for depression prevalence rates but not for global psychopathology or anxiety. Furthermore, for male participants, our results showed a significant association only between online sexual victimization and psychopathology but not for consensual active and passive sexting. However, for the female participants, active sexting, passive sexting, and online sexual victimization were all associated with poorer mental health. Implications for prevention and intervention are discussed.
  • R.T.Coupe, B. Ariel and K Mueller-Johnson, Crime Solvability Factors - Police Resources and Crime Detection (Springer 2019)
    At a time when resources are scarce, not every crime may be investigated as fully as is desirable. Police generally use experience to guide their case screening. This volume demonstrates a new, research-based approach, exploring innovative research on crime solvability as a factor for crime investigation and prevention. Crime solvability is the interplay between forensic science, decision-making, and prediction to determine the likelihood that a crime will be solved. This text discusses recent studies of how solvable cases may be identified, using original sets of police data. It focuses on high-volume crimes such as burglary, assault, metal theft, and cyberfraud. By targeting more cases that can be solved, police departments can manage their resources better and have the greatest effect on arrests, as well as preventing future crimes by these offenders. Topics covered include: Research into the effects of crime solvability and detection outcomes. Studies ranging from less severe, high-volume crimes to severe offences. Effects of resources on investigating and detecting crime. Theoretical resourcing-solvability model of crime detection. Detection complements preventive approaches in containing criminal activity. Chapters on incident solvability and measured use of resources in different investigative stages. Predictive approaches for improving crime solvability. Property, violent, and sexual offenses. Crime Solvability Factors: Police Resources and Crime Detection will be of interest to researchers in criminology and criminal justice, particularly with an interest in quantitative and experimental research and police studies. It will also be of interest to policymakers and police organizations.
    ISBN: 978-3-030-17159-9

Research projects