The Sunnyside Police Department received a report of shoplifting at the store on Yakima Valley Highway just before noon. While officers were on the way, the suspect fled the store, and a store employee followed him. Police say the man then either fell or jumped into the Sulphur Creek Wasteway.
SPD says the employee then went into the canal to try to rescue the suspect but was unable to save him.
Firefighters and police officers were eventually able to pull the man from the canal, but he was found to be dead.
Police have not yet identified the man. The case is still under investigation.
An autopsy is scheduled for Thursday.