Methods and systems monitor activity in a retail environment, such as activity in a display area (e.g., aisle) of the retail environment. A convolutional neural network is used to detect objects (e.g., inventory items) or events (e.g., instances of people picking up inventory items from shelves). Various algorithms may be used to determine whether suspicious activity occurs, and/or to determine whether to trigger alerts. Monitored/detected activity may be stored in a database to facilitate a deeper understanding of operations within the retail environment.