A teenager who walked among protesters in Kenosha, Wis., carrying a military-style semi-automatic rifle was arrested and faces a charge of first-degree intentional homicide in connection with shootings that left two people dead on Tuesday night. Kyle Rittenhouse, a 17-year-old Illinois resident, appeared on multiple videos taken throughout the night by protesters and bystanders who chronicled the events as peaceful protests gave way to chaos, with demonstrators, armed civilians and others facing off against one another and the police in the darkened streets. The New York Times’s Visual Investigations unit analyzed hours of footage to track Mr. Rittenhouse’s movements in the moments leading up to, and during, the shootings. Mr. Rittenhouse was arrested early Wednesday in his hometown, Antioch, Ill., which is about 30 minutes southwest of the protests in Kenosha, just over the state line. Multiple posts on his social media accounts proclaim support for pro-police causes like the...