NBC NEWS- The investigation into the disappearance of Caylee Anthony, 2, has entered its fourth week.

Caylee was reported missing on July 15.

Her mother, Casey Anthony, has been held at the Orange County, Florida Jail since July 16 on charges of felony child neglect.

Casey Anthony continued to deny visitors as the search continued over the weekend to find her 2-year-old daughter, Caylee.

Meanwhile, detectives are planning to use a new technique to examine evidence, officials with the Orange County Sheriff's Office said.

Anthony refused to see her parents at the Orange County Jail on Sunday.

The visit was scheduled for 9 p.m., and her mother, Cindy Anthony, said she had no idea why the visit was canceled.

"Maybe it's based on me canceling my appointment with her the other day," Cindy Anthony said.

Dive teams searched lakes around the Anthony home and found three stolen cars on Friday.

Sheriff's officials said it was part of their normal training.

The family also honored Caylee's third birthday with a gathering on Saturday.

They received cards and gifts from people as far away as New York.

Cindy Anthony said the only thing she wanted to share with her daughter on Sunday night was that she was there for support.

"The only reason that George and I were going to try to see her today was just to see how she was doing after yesterday," Cindy Anthony said.
Another visit is planned between Casey Anthony and her parents on Thursday.