The suspect in an armed robbery kills himself after a standoff in Custer

RAPID CITY, S.D. (KOTA TV) - On Tuesday, an armed robbery that started in Rapid City ended as a standoff in Custer, with the suspect taking his own life.

An image from the scene of Tuesday night's standoff in Custer

Around 3 P.M. Rapid City Police responded to a report of an alarm at Boyds Drug Mart on E. Saint Patrick Street.

Witnesses said a man entered the store, went to the pharmacy counter, showed a gun, and demanded prescription medication. The staff complied and the man left.

Witnesses were able to give a description of the suspect's vehicle, a black pickup truck, and the license plate.

Around 3:45 P.M., a Custer County Sheriff's Deputy spotted the pickup on Highway 385 north of Custer.

The deputy tried to pull the pickup over, but the suspect did not stop.

Law enforcement was able to stop the vehicle west of Custer.

When law enforcement surrounded the pickup, they saw the suspect pointing a gun at himself. Officers tried to negotiate his surrender, but around 7:30 p.m., he shot and killed himself.

First aid was administered, but the man was pronounced dead at Monument Hospital.

The Pennington County Sheriff says the way the multiple jurisdictions worked together was well-executed.

"I think it flowed very well in terms of the response," said Kevin Thom, Pennington County Sheriff. "There was good coordination amongst all the agencies, from Custer State Park, to Highway Patrol, the Police Department, the Sheriff's Office, Custer County. There was good communication all coordinated through our joint dispatch here, which did a wonderful job during the event."

Rapid City Police describes maintaining a good working relationship with other law enforcement agencies in the area.

"This is one more example of that close working relationship that we enjoy, not only with our counterparts at the Pennington County Sheriff's Office, whom we share a building with, but with other law enforcement agencies around the area," said Brendyn Medina, Public Information Officer for the Rapid City Police Department. "Even though we may be responsible for different jurisdictions, we recognize that crime doesn't tend to stay in one jurisdiction."

Police will not released the name of the suspect until the family and next of kin are notified.

We reached out to Custer County Sheriff's Office for an interview, but they were unavailable to comment at the time.