Police looking for two children missing since 2004 found a shallow grave Sunday containing human bones, and the children's mother said she had been told they were likely the remains of her son and daughter.

Tina Porter told the Kansas City Star that Independence police officers arrived at her house Sunday morning to tell her that they had found the remains of her children, Sam and Lindsey Porter, in the woods in Sugar Creek, about eight miles from Kansas City.

"Maj. (Gregg) Wilkinson said they were 99 percent sure that it was Sam and Lindsey," she told the newspaper.

"It was like watching a movie," she said. "I saw the police cars drive up, and my first thought was that they were coming to tell me they'd found Sam and Lindsey alive. I feel so sick. It just doesn't seem real."

Police would not confirm that the bones were those of the children. Tom Gentry, a spokesman for the Independence Police Department, said the remains found had not been identified.

"We want to be very cautious before we make any definitive statements," Gentry said. "Whatever we have to say, we're going to be sure that it's right."

Gentry said if dental records are intact, identification could be made quickly.

Sam and Lindsey Porter were 7 and 8 years old when their father, Dan Porter, picked them up from his estranged wife on June 5, 2004, for a weekend visit. The children haven't been seen since.

Dan Porter, 44, was convicted in February 2006 of parental kidnapping with the intent to terrorize his ex-wife and sentenced to 38 years in prison.

The land where the bones were found is in a wooded, industrial area near Sugar Creek. Investigators looking for the children had searched the area before, and it was where Dan Porter used to poach deer.

It also is where Dan Porter and Tina Porter met on the day he took the children. Police said he asked Tina Porter to meet him near the area to exchange vehicles with him.

After his arrest, Porter told authorities several stories about what he had done with his children, including that he had cut them up and that he had strangled them.