Investigators searching for Lisa Irwin plan to question the missing Missouri infant's two brothers later this week.
The boys, ages 5 and 8, have not spoken with police since Oct. 4 -- the day the 10-month-old was reported missing, Kansas City police told The Kansas City Star.
"This will be the first time we've had a chance to interview them since then," said Kansas City Police Officer Darin Snapp, according to ABC News. "We have not been allowed access to the children until [parents Deborah Bradley and Jeremy Irwin] agreed to bring them in this Friday."
Lisa Irwin's parents believe she was kidnapped from her crib while the family slept. Her brothers were home on the night of their sister's disappearance and may have information that could aid in the search, investigators said.
The boys, identified by CNN as Lisa Irwin's half-brothers, will be questioned on Friday by an expert in child forensic interviewing, not detectives, according to The Star.
SEE PHOTOS FROM THE SEARCH FOR LISA IRWIN (story continues below):
Authorities will also take "non-intrusive" DNA samples from the boys in an attempt to help rule out "unknown" DNA samples collected from the family's Kansas City home, ABC News reports.
Investigators also say they want to speak with Lisa Irwin's parents.
"We need them to sit down apart from each other, with detectives, and answer the tough questions detectives have for them concerning what they may or may not know about anything, who came and went [the night Lisa disappeared]," Kansas City Police Capt. Steve Young told ABC. "There's a whole list of things that they may know."
Bradley and Irwin -- who have criticized investigators for treating them like suspects -- claim they are willing to sit down with police separately, CNN reports.
However, they reportedly don't want to take part if there are no lawyers present, or if detectives enter the interviews with assumptions of guilt or launch accusatorial lines of questioning.
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