As the police prepare to question Lisa Irwin's older brothers in an attempt for new insight from the family, private investigator Bill Stanton adamantly believes that the missing 11-month-old baby is still alive, RadarOnline.com has exclusively learned.

"Until they find a body, in my mind that baby is still out there and alive," Stanton told RadarOnline.com in an exclusive interview. "She didn’t just evaporate, someone took her."

As RadarOnline.com previously reported, Lisa’s parents Jeremy Irwin and Deborah Bradley have agreed to let the authorities question Lisa's big half-brothers, Michael, 5, and Blake, 8, on Friday about the night she went missing from the home.

Police are investigating a possible sighting of baby Lisa Irwin after witnesses spotted two women with an infant that matched the missing 11-month-old's description, and RadarOnline.com has exclusive confirmation from the private investigator in the case.

"Two women were in a diner with a baby who fits the description about an hour-and-half away in Manhattan, Kansas," private eye Bill Stanton told RadarOnline.com in an exclusive interview.

"When they were approached they walked out and a police APB is out searching for their car," revealed the investigator, who is busy working the case.

Missing baby Lisa Irwin now has yet another high profile name on her side after her parents hired suspected killer Joran van der Sloot's former attorney, RadarOnline.com has learned.

Prominent New York City defense lawyer Joe Tacopina announced in a press conference on Monday that he will join the team of people representing Kansas City, Missouri couple, Jeremy Irwin and Deborah Bradley, reported NBC Action News.

Tacopina is best known for representing van der Sloot, the prime suspect in the murder of Alabama teen Natalee Holloway in Aruba, who is currently in prison in Lima, Peru awaiting trial for the murder of Stephany Flores.

As the weeks mount since baby Lisa Irwin’s parents last saw their little girl, the private investigator who they have brought in to help with the search spoke to RadarOnline.com.

“There is a window of time and it gets smaller every day,” Bill Stanton told RadarOnline.com in an exclusive interview.

The former New York City cop turned private eye arrived in Kansas City, Missouri last week to help distraught parents Jeremy Irwin and Deborah Bradley find 10-month-old Lisa, who was last seen sleeping in her crib at their home at 10.30 p.m. on October 3.

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The search for missing baby Lisa Irwin got bigger Sunday morning. The Missouri National Guard deployed 25 members to aid the 50 law enforcement officers already on the scene in the hope of locating the missing girl.

Jerry Schmidt, an expert in large scale searches with the National Center for Missing and Exploited Children, is coordinating the effort which has Guardsmen and other personnel literally standing shoulder-to-shoulder as they comb through a field near the Irwin family home.

This is the second search of this field, and follows a day of dead end leads.

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Diapers found in an abandoned nearby house were thought to have been a clue, but were determined not to be connected to Lisa. A handyman was arrested in the area for an unrelated crime and was questioned about the baby. He was ruled out as a suspect.

The 11-month old Lisa was reported missing early on October 4 after her father came home from his night shift job and said he found her crib empty and the front door unlocked. Lisa's mother Deborah Bradley told cops she'd last seen the infant when she'd gone to bed at 10:30 pm the previous night.

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As RadarOnline.com has reported, an anonymous benefactor has paid to bring in private investigator Bill Stanton to work with the family, and has also put up a $100,000 reward for information leading to the baby's safe return.

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The cousin of missing baby Lisa Irwin has made a heartfelt plea for her return, insisting he would give his life for her safe return.

The tot has been missing for 12 days after she disappeared from her crib at her parent's Kansas City home and the family is desperate for new leads.

"I'd gladly give my life to bring Lisa home safely," Mike Lerette told Good Morning America. "We're hanging in there. Please, please, please keep praying."

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As RadarOnline.com previously reported, a $100,000 reward has now been offered for any information resulting in Lisa's return.

And the same generous benefactor has employed the help of private investigator Bill Stanton to assist with the investigation.

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"I hope this opens up someone's heart or someone's eyes and they realize this is serious and we can get Lisa home safe and sound," said Stanton.

The 10-month old has not been seen since October 3 when her father Jeremy Irwin said he came home at 4:30 am from his night shift job and found his daughter's crib empty.

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He claims the home's front door was unlocked, the family's cell phones were gone and a window screen had been broken open.

Lisa's mother, Deborah Bradley, has said she last saw the baby when she checked on her at 10:30 pm before going to bed.

Police have not publicly named any suspects and no arrests have been made.

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The search for missing Lisa Irwin was stepped up even more on Friday as $100,000 was offered as a reward for information leading to safe return of the Missouri baby, RadarOnline.com has learned.

Meanwhile, the private investigator on the case, Bill Stanton, exclusively told RadarOnline.com that he is “confident” Lisa will be found.

"If I wasn’t feeling hopeful I wouldn’t be here, but I can’t say what new leads we have," the former New York City cop explained.