CHICAGO CBS) — Thirteen months after nine dogs died in the back of a sweltering pickup truck, Indiana State Police have filed charges against the truck’s driver and owner.

Last July, it was over 90 degrees outside when 18 dogs were found in the back of this pickup truck in Lake County. They were supposed to be taken from O’Hare International Airport to Michigan, but half of them didn’t make it.

During the year-long investigation, the Indiana State Police obtained a similar truck and attempted to recreate the circumstances.

“After one hour and 55 minutes of simulation, the temperature inside the truck had already risen to 32 degrees. There were tears that day because the emotions were overwhelming as we saw the dogs suffering,” said Sergeant Glen Fifeld of the Indiana State Police.

At a news conference on Tuesday, officials said two men, the driver and owner of the truck, are now charged with 18 counts of animal neglect.

Each charge could bring them a year in prison and a $5,000 fine.