A motorcycle crash killed a man and woman riding on Interstate 394 Sunday afternoon, the latest in a series of fatal crashes..

Sunday's wreck happened about 1:40 p.m. as the motorcycle was heading from Hwy. 100 to eastbound I-394 in St. Louis Park, according to the State Patrol. The male driver and his female passenger, a 58-year-old woman from Somerset, Wis., were killed.

There was no immediate word on what led to the crash. The victims' identities have not been released.

Dr. Ernest W. Swihart Jr., an award-winning Twin Cities pediatrician, was killed Thursday when he crashed his motorcycle into a tree in the Black Hills of South Dakota, authorities said.

Swihart, 71, of Minnetonka, was on a yearly camping trip with his wife, the South Dakota Highway Patrol said. He was heading down a hill, "entered a curve and locked the brakes on his motorcycle, which caused him to lose control, enter the ditch and collide with a tree," the patrol said. He was wearing a helmet.

Swihart was a behavioral pediatrician in Minnetonka with South Lake Pediatrics, a practice that he helped found in 1974. He also was on the clinical faculty at the University of Minnesota. He received a liver transplant a year ago Monday after a diagnosis of nonalcoholic steatohepatitis, or fatty liver disease, two years ago, according to his CaringBridge Web page.

In 1997, he won a Minnesota Book Award for co-authoring "The Manipulative Child." In 2013, he received the U's Department of Pediatrics Homer Venters Award. He appeared on ABC-TV's "Nightline" in 2011 to discuss the use of medication for children with attention deficit hyperactivity disorder.

In yet another incident, Janice K. Theisen, 57, of White Bear Lake, died Friday at Hennepin County Medical Center in Minneapolis. She was riding on Sept. 13 in Wright County south of Buffalo with a group of motorcyclists that began slowing down, the State Patrol said. Theisen braked hard and lost control. She was not wearing a helmet when she crashed.

Paul Walsh • 612-673-4482