CROWN POINT, Ind. -- Authorities said a semitrailer slammed into a pickup truck that had slowed down on Interstate 65 in northwestern Indiana, killing all five people riding in the truck.

Indiana State Police said the wreck happened at about 4 a.m. Friday near the Lake County city of Crown Point.

Trooper Khari Walton said the southbound semitrailer was cresting a hill when it came upon traffic that had slowed for a vehicle being towed from the highway.

The driver of that truck, Forest Stover, was unable to stop in time and hit the pickup truck, pushing it into another semi, driven by George Hack.

The pickup truck was crushed and caught fire, and the blaze spread to Stover's truck, Walton said.

The victims were identified as Brian W. Workman, 33; Joanna Workman, 31; Ashley Workman, 13; Tyler Workman, 8, and Ryan Workman, 1, all of Hobart.

Neither Stover nor Hack was injured. Southbound traffic was closed for six hours while investigators cleared the scene.