STILWELL, Oklahoma - The Oklahoma State Bureau of Investigation released surveillance video of a June 9 attempted robbery of an armored truck in Adair County as agents continue to search for the suspect. 

An unidentified man placed a threatening letter on a Loomis Truck that was parked in front of the Stilwell Walmart, agents said.

View the video below:

"We're hoping to get the public's help in trying to identify the suspect in this case," agents said.

The letter threatened violence against the armored truck driver and his family if he didn't follow instructions about dropping off money, according to the OSBI.

The Loomis employees asked for help from an Adair County Sheriff's deputy who was inside the store. Stilwell police also got involved and then requested assistance from the OSBI. 

The OSBI initially released a photo of the man on June 12, but they're hoping someone might recognize the man from his walk and mannerisms on the video. 

OSBI is hoping to reach people in Adair and Sequoyah counties as well as those in the Ft. Smith and Fayetteville, Arkansas, areas. 

"We're thinking there's a good possibility that our suspect is from that area," agents said.

Anyone with information about the man is asked to call the OSBI hotline at 1-800-522-8017.