Tymkowych said that dogs had been used in the investigation initially but proved unsuccessful. He said that investigators working the case do not believe Kayleah had any problems with drugs or alcohol, and have not found anyone who may have wanted to harm her.
"We have no evidence that there was any foul play," he said. "At this point, everything is still a question mark for us."
The eight-block area where Kayleah would have walked to get to the party is well-populated and safe, according to authorities.
Wilson also said that she had no concern about her daughter walking alone and that the neighborhood is not dangerous.
"We all walk everywhere, we don't even have a car," she said. "It's not a bad neighborhood."
Wilson described her daughter as "loving" and "trusting," and said that she's always been well-behaved.
Other than that, Wilson said her daughter is a typical preteen who has a crush on one of the singers from the folk band Celtic Thunder.
On the morning of the day she disappeared, Wilson said her daughter had gone to church with her and had been happy during a lunch at a local restaurant with her grandmother.
"I just want everyone to help find her. I don't care if you're in this state or in another country, just help," Wilson said.
ABC News' Clayton Sandell contributed to this report.