The last of three homicide suspects in a fatal hit-and-run last week in Andover was arrested Monday morning.

Loren J. Gafner, 19, of St. Francis, is the driver suspected in the death Friday of 17-year-old Tristan G. Robinson, of Nowthen, according to the Anoka County Sheriff's Office.

Robinson "was allegedly willfully, intentionally struck with a car by a driver who intended to do so" as part of a robbery, read a statement from the Sheriff's Office.

Robinson was killed on 141st Lane NW. near Palm Street; two teenage boys were arrested earlier.

Sheriff's Cmdr. Paul Sommer said authorities also found the car that ran over Robinson.

Gafner had sought refuge at a residence in Isanti County, Sommer said. A man in the home realized who the intruder was and contacted authorities, prompting Gafner to flee.

A state trooper responding to the resident's call saw Gafner walking north of Isanti on 305th Lane NE., Sommer said. The trooper approached and made eye contact with Gafner, and the suspect fled into the woods.

Law enforcement set up a perimeter and Gafner was arrested with the assistance of a K-9 from the Ramsey County Sheriff's Office, Sommer said.

The vehicle was found roughly 5 miles away parked on property in Bradford.

In describing Robinson's death, Sommer said Sunday, "This was not a road and driving mishap as it was originally reported. What has come to light is that it was a purposeful act perpetuated as part of a robbery scheme." On Twitter, Sommer called it a case of second-degree murder.

An investigation showed that the car, occupied by three teens, ran over Robinson as part of a plot to rob him of a small amount of marijuana. Several details about the incident came from the teenagers' classmates, Sommer said.

Robinson's mother, Angel Westerberg, said her son was "a kid with the biggest heart," and had many friends.

He delighted in fishing and four-wheeling at his grandparents' home, and was a talented rapper, Westerberg said.

"I need justice for my sweet Tristan," she said. "He was my whole world."