PESOTUM — Authorities think a northwestern Indiana man killed his wife, then drove to Champaign County on Friday, where he killed himself.

Champaign County Coroner Duane Northrup said Saturday that both Jaime Rodriguez, 52, and his wife, Maria Rodriguez, 50, of Ogden Dunes, Ind., died of multiple stab wounds.

Their bodies were discovered Friday afternoon at an Interstate 57 rest area near Pesotum on the southbound side of the highway. Their deaths are being investigated by the Porter County, Ind., Sheriff’s Department, the Illinois State Police, and Northrup’s office.

Northrup said Indiana State Police sent out an alert Friday to other police agencies that they were looking for the Rodriguezes’ car. Some time after 1:20 p.m., an Illinois State trooper from the Pesotum post saw a car matching the description at the Illini Prairie rest area and stopped.

Northrup said Mr. Rodriguez’s body was in the back seat, a knife protruding from his body. Mrs. Rodriguez was found in the trunk, her body wrapped. Although both had been dead a while, they were pronounced dead at 2:20 p.m.

A spokesman for the Porter County Sheriff’s Department in Valparaiso, Ind., did not return a call Saturday seeking information on what happened in that county that led police to be looking for the couple. Northrup said he was told that Mrs. Rodriguez had not shown up for work earlier this week.

“I believe he died in Illinois. I believe she died in Indiana. I don’t know when,” Northrup said. “They’re still trying to piece together what happened in Indiana.”

Northrup said the couple has three adult sons, who were notified of their parents’ deaths by police in Indiana.

An inquest may be held later, he said.