April 13, 2021 | 12:44 PM Two hit-and-run crashes left one man dead and another with possibly life-threatening injuries in Braintree and Somerville Monday night and early Tuesday morning. In Braintree, a man was struck and killed by a driver on Interstate 93 southbound near Exit 6, according to Massachusetts State Police spokesman Dave Procopio. Troopers responded around 4:25 a.m. Tuesday. The man, a 42-year-old Boston resident whose identity has not been released, was found dead at the scene, Procopio wrote in an email to reporters. Troopers were working to establish a description of the vehicle involved later Tuesday morning. An investigation indicated the pedestrian entered the highway south of Exit 6 and was struck near “the second and third lanes,” Procopio wrote.