Missing Missouri 11-month-old baby Lisa Irwin's two older brothers, who were in the house the night she disappeared, will submit to interviews with investigators and provide DNA samples.
Child specialists spoke to the boys on Oct. 4, the day after Lisa's disappearance, but investigators have not had access to Lisa's 5 and 8-year-old half brothers since then.
"This will be the first time we've had a chance to interview them since then," Kansas City Police Officer Darin Snapp told ABCNews.com today. "We have not been allowed access to the children until [parents Deborah Bradley and Jeremy Irwin] agreed to bring them in this Friday."
"We are expecting to collect DNA samples," Snapp said. "It will be very non-intrusive, pretty much just a Q-tip swab." Snapp said some DNA samples, currently in a lab, that were collected from the house are labeled "unknown" and they want to use the boys' DNA to eliminate some of the unknown samples.
"We spoke to one for 50 minutes and the other for 30 minutes," Snapp said. "They were woken up very early in the morning and, due to their ages, we didn't want to interview them for too long that day."
Snapp said there will not be any detectives involved in Friday's interviews. They will be conducted by child specialists.
Investigators want to "bring them back to see if they remember anything that might be able to help find their younger sister," Snapp said. The boys were reportedly sleeping with Bradley in her bed when Lisa disappeared and may have heard noises in the house.
Tensions between investigators and Lisa's family have continued amidst discord about Bradley, 25, and Irwin's, 29, level of cooperation, but police are still intent on interviewing them.
Investigators want Lisa's parents to submit to separate interviews and answer a list of "tough questions" that detectives "need answered."
Kansas City Police Capt. Steve Young made his statement Tuesday as the investigation into the toddler's disappearance entered its fourth week without any suspects or leads to the girl's whereabouts.
"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]," Young told ABCNews.com. "There's a whole list of things that they may know."
Young said he is "not disputing" family attorney Joe Tacopina's claims that the family has cooperated and answered other questions, such as specific questions regarding tips and leads. But that is not sufficient, he said.
"The bottom line is detectives need to sit down with them unrestricted and they need to answer questions that we need answered," he said.
The captain rejected any suggestion that the case has hit a dead end.
"It would be far from reality to call this a cold case," Young said. "We're still looking at everything."
Police have received over 975 tips and have cleared almost 800 of those tips.
Baby Lisa has been missing since the night of Oct. 3 and an anonymous benefactor is offering a $100,000 reward for her safe return or the conviction of whoever took the little girl.