Police said a Bonney Lake couple in their 20s and their 6 to 8-month-old boy were killed when a concrete barrier and construction debris fell from a highway and onto their passenger truck Monday.

East Pierce fire said workers in Bonney Lake were installing a sidewalk on Highway 410 when a concrete barrier, a permanent part of the overpass, fell onto the cab of the truck on Angeline Road East.

The concrete barrier is about 20 feet long.

At first, police could tell the driver was killed, but firefighters did not know if others died. After workers removed the debris, three people were extricated -- a husband, wife and their baby. The roads were closed for the investigation until 10:15 p.m.

The sidewalk installation is a City of Bonney Lake project.  Police continue to investigate what role, if any, the construction played in the barrier falling.