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Prosecutors added a surprising new wrinkle to the Casey Anthony trial Tuesday by raising the possibility that the Florida mother accused of killing her daughter stole her defense from a woman she spent time with in jail.

Authorities notified the court while the jury was out that they are looking into whether Anthony's claim that her 2-year-old daughter, Caylee, drowned in a pool was influenced by April Lynne Whalen, a former jailmate whose son drowned in a pool.

Prosecutor Linda Drane Burdick said there was no immediate plan to call Whalen as a witness, but the similarities in the two stories are under investigation.

"Ms. Whalen indicates to law enforcement that she did not talk to Casey Anthony," Burdick told the court. "However, she doesn't remember if she talked to other inmates (about her son's death)."

Both say their children died in family pools and were discovered by the children's grandfathers. Whalen, however, reported her son’s drowning right away, and authorities never considered it suspicious.

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There's no evidence to indicate that the two spoke at the Orange County Jail from June 4 to June 8, 2009, a jail spokesman told FoxNews.com, though conversations sometimes can be overheard through cell walls. Authorities are investigating Whalen’s phone records from those five days, a sheriff’s spokesman said.

During that time, Anthony was in protective custody, and Whalen was being treated for a medical condition. So when Anthony would leave her cell for exercise, other inmates in that part of the jail were required to be locked in their cells.

Anthony is on trial on a charge of first-degree murder and potentially faces a death sentence if convicted. She has pleaded not guilty.

Jose Baez, Anthony’s attorney, said in opening statements that Caylee was found dead in the pool by her grandfather, George Anthony, who then helped cover up the death in 2008. George Anthony denied that, and the prosecution has tried to portray Casey Anthony as a compulsive liar who partied instead of reporting her daughter missing.

In Whalen’s case, her son Isaiah was found Christmas Day 2007 by his grandfather at the bottom of a dirty pool that was dark green with large amounts of tree debris floating in it, according to the incident report. Attempts by the grandfather to perform CPR were unsuccessful. Whalen reported the incident to authorities the same day.

Whalen, 30, has a long booking record of non-violent felonies and misdemeanors, with charges ranging from driving with a suspended license to possession of methamphetamine.

A connection to Whalen potentially would be damaging to Anthony's case, because it could undercut one of the key components of her defense -- that Caylee's death was an accident, or as Baez put it, a “common tragedy.”