De Soto ? A husband and wife died Tuesday after a semitrailer they were in went through a bridge guardrail and fell into the Kansas River.

“I was following it and all of a sudden it crossed over and hit the guardrail and Bam! it went over the side,” said Bob Hemphill, 54, of Linwood. “I’d never seen anything like it.”

Hemphill, who was on his way to De Soto to buy groceries, said he stopped and called for help on his cell phone.

The accident was reported at 8:19 p.m. on the Wyandotte Street bridge, said Tyler Butts, media spokesman for the Overland Park Fire Department, which was called to assist De Soto firefighters.

Two people were in the cab of the tractor-trailer and both were dead at the scene, Butts said. An air ambulance helicopter was initially called but was then turned away.

The identities of the victims had not been released late Tuesday, but authorities did confirm that they were married.

The tractor was southbound when it crossed over and went off the bridge’s east side, Butts said.

Hemphill said he only saw one person who was trying to get out of the cab after it hit the water. He said he saw a man who appeared to be trapped but had his head above water.

The Lenexa Fire Department and police from Overland Park and Olathe also responded. An Overland Park Police underwater search team went into the water to try to rescue the victims.

Some diesel fuel spilled in the water and a hazardous waste crew was called in, Butts said.