About 10 a.m., Lee's husband reported her missing. He told police that after his wife left with the dog, he went to an appointment. When he returned, he found the dog running loose.
Clothing was found at the site of the Hummer incident, and it was hers, the husband told authorities.
About 10 p.m., a woman's body was found at a state Department of Transportation lot on Rockwood Road near I-95, about a half-mile from where Lee disappeared. An autopsy Tuesday confirmed the deceased as Lee.
Smith, who lives less than a mile from Lee's home, was driving a red Hummer with tinted windows Monday evening when he was stopped and arrested.
After his arraignment, Smith was being held without bail at Howard R. Young Correctional Facility, also known as Gander Hill Prison, in Wilmington.
Ellen Casson, 62, said she knew Lee for years through their participation in the Brandywine Hills Community Association.
Lee was a longtime block captain, a former treasurer of the association, and "just very committed to the neighborhood," which counts among its residents U.S. Sen. Tom Carper, Casson said.
"It's just a shock, a terrible shock," she said.
On Facebook, Smith identified himself as married to Jasmin Smith, 28. On her Facebook page, she listed their marriage date as May 20. Both listed their residence as Fort Drum, N.Y.
He attended Concord High School in Wilmington and Alabama A&M University, according to his Facebook page.
Both he and his wife posted multiple photographs of Smith in uniform, including one of an apparent prank in which a fellow soldier was bound like a captive with duct tape.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.
Inquirer staff writer Robert Moran contributed to this article.