ORLANDO, Fla. -- The Orange County sheriff said there is no credible evidence to support a contention by the family of a missing Orlando girl that the child was kidnapped.

---

IMAGES: Caylee Photos | Casey Photos Surface

---

"Right now, I don't think there is any credible information on the kidnapping theory," Sheriff Kevin Beary said. "If it is accidental, then I need to know that and people with credible information need to come back and tell me that."

Caylee Anthony's mother, Casey, is jailed in connection with the case.

Beary said Casey Anthony needs to talk with deputies.

"I'm not going to beat up on anybody because it's a very tragic situation (but) we need her cooperation," Beary said. "She was probably the last person to see Caylee."

Beary said about 1,700 tips have been called in concerning the case.

He said his team has found no one with credible information.

Family Lashes Out

Meanwhile, Caylee Anthony's grandparents lashed out at news reporters Thursday over a question yelled at them as they walked to see the child's jailed mother.

"Do you have anything to say about a new theory that Caylee (Anthony) may be dead and that it may be an accident?" a reporter asked.

"Shut up," George Anthony screamed as he moved toward the reporter. "Shut up."

Caylee's grandmother, Cindy, stepped between her husband and the reporter. She then said the media have hampered tips from the public before walking off.

"That is the reason why I got a phone call at 11 p.m. last night and the lady was crying because of that kind of stuff on the news that she held back for four weeks calling in a tip because she was afraid and they spotted Caylee again."

George and Cindy Anthony spent 45 minutes on a video conference call with their daughter at the jail. Both left the Orange County Jail without comment.

Mom Stopped Mentioning Caylee

Meanwhile, an interview with a former roommate of Casey Anthony's boyfriend shed some light on how the woman acted while her daughter was missing and before her mother called the authorities.

A man named Clint House -- a former roommate of Casey Anthony's boyfriend, Tony Lazarro -- spoke to Fox News about the woman's demeanor.

"Between June 16 and July 1 when you moved out, was Casey still coming to see Tony and spending the night?" Fox News anchor Greta Van Susteren said.

"Yes, it became more frequent and being almost every single night she was staying there," House said.

"Do you remember that week, right after Father's Day?" Van Susteren asked. "Anything unusual that week?"

"Nothing unusual besides the fact that Caylee was never there anymore," House said. "We always asked where Caylee is at, (and she'd say) 'Oh, she's with the grandparents or she's at the beach with the nanny. That didn't strike me as unusual at the time. Other than that, nothing."

House continued to say that at a certain point Casey Anthony stopped mentioning Caylee even when they asked about her.

He said looking back at the events, some of Anthony's behavior is troubling.

"Wouldn't you be surprised if someone who was hanging out with you and your friends, all of the sudden her daughter is missing and she is out partying?" House said.

House said Casey Anthony claimed she went to work every day and that she was going back to school.

He said she told him the child's father was on the way to Caylee's birthday party and was killed in a car crash but added that he had no way of knowing whether or not she was lying.

Detectives Zero In On Calls

Also, detectives are zeroing in on Casey Anthony's cell phone records, Local 6 has learned.

Casey Anthony's cell phone records from June 16 -- the day investigators believe something may have happened to her daughter Caylee -- show she made nearly a dozen calls in less than five hours, records obtained by Fox News Channel showed.

Anthony called her mother seven times, her dad once, her boyfriend and two other friends, the records showed.

The woman's cell records from June 17 were not available but on June 18, the records showed Casey Anthony tried calling her mom and dad six times in less than an hour.

Investigators are using cell-tower mapping to pinpoint the areas where the calls were made.

Watch Local 6 News for more on this story.