KINGFISHER COUNTY, Okla. (KFOR) – The Oklahoma State Bureau of Investigation says the four people killed Sunday near Hennessey were executed.

An investigation is underway in Kingfisher County after four people were found dead and another hurt following a violent attack at a marijuana grow farm.

The OSBI said at approximately 5:45 p.m. Nov. 20, a male suspect entered a building on the property near EW 600 and NS 2760.

He was inside that building for ‘a significant amount of time’ before executing several employees inside.

Three men and one woman – all Chinese Nationals – were shot execution-style. Another person, also Chinese, was shot multiple times and flown to OU Health.

“Based on the investigation thus far, this does not appear to be a random incident,” said OSBI officials. “Law enforcement believes releasing the identity of the suspect at this time will put additional individuals in danger.”

However, authorities say they believe the suspect to be another Chinese National.

Officials say next of kin notification is pending due to a language barrier.