The problem of missing persons is often overlooked in the Indian criminal justice system, despite the significant distress experienced by families. While not legally considered crimes themselves, missing persons cases can have criminal underpinnings. Pre-pandemic data (2017-2019) showed an increasing trend in reported cases in India, suggesting the need for a better understanding of the factors influencing reporting. The COVID-19 pandemic and subsequent lockdowns in Tamil Nadu exacerbated socio-economic challenges, likely affecting missing person reporting. This study aims to evaluate the impact of mobility restrictions on the reporting and registration of missing persons during the pandemic.

Existing research highlights the complexity of missing persons cases, the challenges faced by law enforcement in locating missing individuals, and the emotional toll on families. Studies worldwide have explored innovative methods for locating missing persons, such as risk factor assessment and community engagement. However, there's a lack of data on the pandemic's impact on missing person reporting, particularly in the Indian context. The paper also notes that different countries have different challenges, such as war-torn areas, which are not present in India, making the Indian context unique.

This study employs a natural experiment approach, leveraging the COVID-19 lockdowns in Tamil Nadu as a means to analyze the impact of mobility restrictions on missing person reporting. Data on registered missing person cases from the Tamil Nadu police over eleven years were used. The study divided the pandemic period into eight time windows reflecting different lockdown phases (complete and partial lockdowns, and post-lockdown periods). Google's COVID-19 Community Mobility Reports provided mobility data across six community spaces (retail and recreation, parks, groceries and pharmacies, workplaces, transit stations, and residential areas). The DeepAR forecasting algorithm, a recurrent neural network (RNN) based model, was used to predict the daily count of missing persons under a counterfactual scenario (no lockdowns). This allowed for the calculation of the causal impact of lockdowns on reporting. The Shapiro-Wilk test checked for normality assumptions, with the t-test or Wilcoxon sign-rank test used to assess the significance of differences between actual and predicted counts. Cliff's Delta measured effect sizes.

Descriptive statistics showed a significant increase in the mean and mode of daily missing person cases during the pandemic compared to the pre-pandemic period. However, counterfactual analysis revealed a substantial decline in registered cases during complete lockdowns in both waves of the pandemic compared to the predicted values without lockdowns (effect sizes: -0.981 and -0.74 in 2020 and 2021, respectively). This indicates a significant impediment to reporting during periods of restricted mobility. Conversely, the post-lockdown phases showed a significant increase in registered cases (effect sizes of +0.931 and 0.834 in 2020 and 2021), suggesting restored reporting channels. A similar pattern, albeit with smaller effect sizes, was observed for unidentified dead bodies. The study also found a significant difference in mobility levels between Tamil Nadu and Chennai, with Chennai showing more pronounced changes across different lockdown phases and spatial domains. This difference in mobility did not influence the registration rate of missing person reports in a significant way.

The findings strongly suggest a causal link between mobility and the reporting of missing person cases. Restrictions on movement during lockdowns hindered access to reporting mechanisms, leading to a significant underreporting of missing persons. Improved mobility following the lifting of restrictions facilitated higher reporting rates. The study's findings emphasize the importance of ensuring accessible reporting channels for all crimes, even during crises. The similar trends for both missing persons and unidentified dead bodies suggests that a lack of mobility impacts the ability to both report missing persons and to discover and identify unidentified remains.

This study highlights the critical role of mobility in facilitating the reporting and registration of missing person cases. Lockdowns significantly hampered reporting, while improved mobility led to increased registrations. This underscores the need for policies ensuring accessible reporting mechanisms, particularly during emergencies. Future research could explore the impact of other factors (such as socio-economic conditions) on missing person reporting during the pandemic and examine innovative strategies to improve reporting channels during crisis.

The study focuses on Tamil Nadu, India, and its findings might not be generalizable to other regions with different socio-cultural contexts and policing systems. The reliance on Google's Community Mobility Reports for mobility data might introduce biases, though it's a widely used and accessible data source. Finally, while this study focuses on the effect of mobility on *reporting* missing persons, it does not directly address the impact on the overall numbers of individuals going missing.