SUNNYSIDE — J. Guadalupe Martinez-Lopez, 24, was taken into custody as a person of interest in the Monday night triple homicide near Mattawa.

Grant County Undersheriff John Turley said the suspect was the person they were initially looking for in connection to the shooting during the investigation.

The Sunnyside Police Department arrested Martinez-Lopez at a restaurant Tuesday night while investigating a convenience store robbery.

Pasco police Capt. Jim Raymond told the Tri-City Herald newspaper Martinez-Lopez appeared to be the suspect responsible for three armed robberies in Pasco earlier this month. Investigators were still working with witnesses to positively identify the robber.

Martinez-Lopez is suspected to be connected to three unidentified Hispanic men gunned down outside of Mattawa Monday night.

Law enforcement initially located two shooting victims near Road 24.7 Southwest. One was dead at the scene while the other died in an ambulance while personnel from Grant County Fire District 8 attempted to revive the man.

Shortly after the report of the two shooting victims, a motorist reported seeing a man lying in the roadway, about two miles from the first crime scene on Road 26 Southwest. The motorist advised emergency dispatch the man was shot and was not moving.

Authorities advised the man was dead at the scene.

The Grant County Coroner continues the effort to identify the men and notify their families.

Further information was not available.