NORTH LAUDERDALE, Fla. —  The county sheriff said Friday he hopes that the people who threw a newborn boy out of a moving car are feeling remorse and will come forward.

Investigators are trying to identify the couple who threw the boy, believed to be less than an hour old, alongside a busy street Thursday afternoon, Broward County (search) Sheriff Ken Jenne said. The car then sped away.

The 8-pound, 2-ounce boy, whose umbilical cord was still attached, survived with minor injuries and was hospitalized in stable condition Friday.

"I would hope nature would take its course and they would feel the guilt of having abandoned this child, putting it at risk, and will come forward," Jenne told NBC's "Today" show.

State law lets a mother leave a baby at any medical facility or fire station within three days of birth without any questions asked.

"That provides parents or women with an option. You don't have to just abandon your child in way that would endanger his or her life," said Veda Coleman-Wright, a sheriff's office spokeswoman.

A woman stopped and found the baby inside a small plastic bag. She scooped him up and took him to a nearby sheriff's office, and he was transferred to Broward General Medical Center (search).

The good Samaritan, who originally thought the couple had thrown a puppy out the window, was "very distraught, very upset," Jenne said. The woman's name was not released.

Investigators are searching for a white, older-model large sedan that witnesses observed leaving the scene. The baby's rescuer told investigators she observed a man and woman arguing inside the vehicle. But she saw only the back of their heads, Jenne said, and could not provide a good description.

North Lauderdale (search) is about 15 miles northwest of Fort Lauderdale (search).