ORANGE COUNTY, Fla. -- Detectives think they have a solid case against Casey Anthony and Eyewitness News found out Thursday that Casey's own father will testify against her in front of Orange County's grand jury next week.

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Sources told Eyewitness News that prosecutors now have all the forensic evidence they need to ask the grand jury to indict Casey for the murder of her daughter Caylee.

Two members of the Anthony family now have key roles in the case against Casey, her father for what he's going to do and her brother Lee for what he didn't want to do.

Sources told Eyewitness News the Orange County grand jury will hear about high levels of chloroform in the trunk of Casey Anthony's car. The panel will hear how lab tests on the hair and the stain in the trunk will show that Caylee's body was in that trunk and that investigators also believe the little girl's body was at some point in the Anthony's backyard near her playhouse.

The focus on when Caylee was murdered is on the afternoon of June 16, sometime between mid-day, when Caylee's grandfather last saw her alive with Casey, and the evening, when Casey went to her boyfriend's apartment without Caylee.

Eyewitness News has learned George Anthony will testify against his daughter next week before the grand jury about, among other things what he's already told investigators, how in late June Casey prevented him from going near her trunk, which he later found exuded the smell of death.

"Her and I got into a little verbal, she don't want me to go in the trunk," Anthony told investigators during questioning.

George and Cindy Anthony voluntarily gave up DNA samples this week so investigators could scientifically exclude either of them as the source of the hair and stain in Casey's trunk, but investigators had to get a search warrant to get Casey's brother Lee to submit to a DNA test. He also has refused to take a lie detector test for the FBI.

The fact that a grand jury is being called to hear the case at all does not bode well for Casey. In Florida, a grand jury only has to be presented with a case for "capital" crimes, a charge of either first-degree murder or felony murder. It won't be as difficult to convince a grand jury to indict Casey as it would be to convince a regular jury to convict her.

Trial jurors have to convict defendants beyond a reasonable doubt. Grand jurors only have to have probable cause, meaning a reasonable person would conclude from the evidence that Casey committed the crime.

CHARGES EXPECTED TO BE FILED AGAINST 2 PROTESTERS

The protesters confronting Casey are starting to get more organized. They used to be just a group of rowdy people in front of the Anthony house, but now they have bumper stickers and logos.

The Orange County Sheriff's Office will file charges against two protesters for misdemeanor battery. The sheriff's office said the protesters lost control and committed an act of violence on George and Cindy Anthony.

Kathy Harris confronted George Anthony while he was asking supporters for donations and getting the word out about his granddaughter Caylee. Harris is from a new, organized group of protesters called Justice For Caylee. The group has logos and a new sign.

Harris followed Anthony to the location he was raising funds, because she wanted to know why he isn't looking for the child and instead asking others to do it for him. George Anthony called deputies for help when the exchange got ugly.

"They want the right to show their side and what they believe. That's what we're asking too," Harris said.

She believes the child is dead and it's time to look for Caylee and prosecute her mother, the person they think is responsible.

"Someone just disposed of this body like it was trash and there is no justice for this baby," she said.

Meanwhile, Orange County investigators got the last piece of evidence they need to move forward on charges against two protestors. Video shows one protester pull George by the shirt and another push Cindy Anthony. The two protesters face misdemeanor battery charges.

"This is a reminder, don't commit a battery, have control of yourself," Detective Freddie Sams said.

The charges will most likely be filed Friday.