A young driver who killed himself and three Arlington Heights family members in a February crash spent the hours before the collision drinking heavily, sexually harassing a young woman and hitting a bar patron, according to a Des Plaines police investigation.

The 84-page report into the deaths of Kevin and Anita Crawford and their 20-year-old daughter, Kirsten — who died after Piotr Rog, 21, of Des Plaines slammed his Mercedes-Benz into their vehicle on Northwest Highway — determined the crash Feb. 16 was a reckless homicide. No charges will be filed because the driver died, according to the report released Thursday.

And while the report casts a picture of irresponsibility on Rog and his 26-year-old passenger who survived, it also shows a community seeking to help during tragedy.

A nearby resident heard the collision, which he described as “the loudest thunder he had ever heard,” and rushed to the scene while calling the police. When he saw the mangled vehicles, he grabbed a crowbar tool and attempted to pry open the driver’s door on the Crawford’s Chevrolet Impala.

Meanwhile, others used fire extinguishers to quell a blaze in the Mercedes’ engine.

Read more at the Daily Herald.