Crime Exposed: A Buck Taylor Novel (Book 4). Crime, #4

Fresh off investigating the ambush murders of two police officers, Colorado Bureau of Investigation Agent, Buck Taylor and his team are called upon to find a missing journalist, in a case that leads to child porn, and murder, in the much anticipated fourth "Crime" novel.  She was about to thank the Good Samaritan when he reached a huge hand behind her head and in one swift move slammed her forehead into the steering wheel.
The blow was so hard that it cracked the top of the steering wheel. It took two more blows to knock her out. He put the car in gear and, checking once more up and down the highway, pushed the car past the end of the guardrail and stopped it at the edge of the drop-off. The reservoir was still frozen, but he hoped that enough of the thaw had occurred to make the ice thin enough so the car would crash right through it.
He was confident that the snowfall that was underway would cover the hole in the ice. With one last look up and down the empty highway, he closed the door, walked behind the car and gave it a shove. With a grinding of metal against the rock, the car bounced over the edge and rolled down the side of the reservoir, crashing into the ice with a loud bang, and after a second's hesitation, broke through the ice and disappeared beneath the surface.
He stood on the shoulder of the road and watched until the taillights blinked off.