Washington, Mar 15 (IANS): A Japanese Nobel Prize winner's wife, said to be suffering from Parkinson's disease, was found dead at an Illinois landfill hours after the couple were reported missing.

The body of Sumire Negishi, 80, was spotted in Rockford on Tuesday, the Ogle County Sheriff's Office said.

Her husband, Purdue University chemistry professor Ei-ichi Negishi, 82, was found walking nearby and was taken to hospital, CNN reported on Thursday.

The couple lived in West Lafayette, Indiana, and had been reported missing along with their car since Monday, the police said.

The case was under investigation, the sheriff's office said, but no foul play was suspected.

Ei-ichi Negishi shared the Nobel Prize for chemistry in 2010 with two other professors "for palladium-catalyzed cross couplings in organic synthesis."

Purdue President Mitch Daniels mourned the loss of Sumire Negishi. "Throughout a lifetime of love and loyalty, she supported her husband in a career of tremendous contributions to science and to the teaching and training of subsequent generations of top scientists," Daniels said in a statement.

The family said Negishi had been "near the end of her battle with Parkinson's (disease)".