Dad Eyed in Kids' Father's Day Disappearance

Texas cops say the siblings, 7 and 3, last seen Sunday, may have been killed.

June 18, 2008— -- A Texas man suspected in the Father's Day disappearance of his two children remains in police custody as search teams continue to hunt for any sign of the siblings.

Randy Sylvester Sr., 27, was arrested Tuesday on outstanding traffic warrants. He also faces an additional domestic violence charge, and authorities say they fear Sylvester may be responsible for a far more heinous crime.

Sylvester's two children, Randy Sylvester Jr., 7, and Denim Sylvester, 3, were last seen Sunday afternoon near a tennis court outside the family's apartment complex in Pasadena, Texas.

Sylvester originally agreed to take a polygraph test, Pasadena police spokesman Bud Corbett said at a news conference Tuesday, when authorities formally named the father a suspect in the disappearance.

The man also made statements to his wife and mother of the children, Jerilynn St. Cyr, that indicated the children may be dead rather than missing, authorities said. St. Cyr reported the children missing at 9 p.m. Sunday night.

"The father made, according to the mother, multiple inferences that the kids were dead, and it was time to move on," Corbett said. "I think that was the phrase that was specifically used in conveying that information to us."

Corbett delivered grim news that, while the search continues today, authorities believe they may now be looking for the children's remains. "The area and the nature of the search has been revised to include other geographic locations and the possibility that this is a recovery rather than a rescue effort," Corbett said. "But we really don't know at the moment."

Corbett confirmed in an interview with ABC News that a Fort Bend County Sheriff's Office bloodhound tracked Denim Sylvester's scent from the tennis court to the door of Sylvester's apartment and then to his car, which already was processed as evidence and released by police.

As the hunt for the two children intensified, Sylvester became increasingly agitated by the attention the search for his children was receiving.

"I feel like I want to fight all y'all at the same time," Sylvester said outside the apartment building. "All y'all strap up."

St. Cyr is not a suspect in the children's disappearance, Corbett said, and has been provided a safehouse by the FBI. The woman is afraid that someone may try to retaliate against her because of the information she provided police. She is also the victim in the alleged domestic violence incident Sylvester will be charged with, a dispute that occurred Monday night, the day after she reported her kids missing.

Sylvester has provided some helpful information, but Corbett said authorities believe he knows much more. "We would be a lot more successful if he would be forthcoming or straightforward," Corbett said, "and he has been less than straightforward with us the entire investigation."

Grandmother Alanda Sylvester pleaded for her son and his wife to help police find the children, in an interview with ABC News' Houston affiliate KTRK. "If something has gone wrong, let them handle it, but don't let these kids out there for all these days, not knowing what might happen to them," she said.

Texas EquuSearch joined more than 30 detectives assigned to the case Tuesday and continued today to search for any sign of the missing children. Tim Miller, head of the search organization, said that volunteers were combing wooded areas and "easily accessible places to pull in and drop someone without being seen." They are also sifting through garbage collected from the apartment complex.

"We have people working with law enforcement, going through numerous dumpsters that dogs alerted on," Miller told ABC News.

A local businessman offered a fuel truck to help curb the expense of keeping search vehicles on the ground.

Police use of the word "recovery" rather than "rescue" makes the search particularly heartbreaking. "It looks like the best thing that could happen in this case is if we are going to a funeral for these two little children next week," Miller said.