Police investigating claims that a Polish man imprisoned and raped his daughter were seeking DNA samples Tuesday from the two children she says he fathered.

The 21-year-old woman told police she was held captive for six years and forced to give the two boys up for adoption. Police were trying to find them to determine if the accused man is their father.

But neighbors say they often saw the woman outside the family's home and that she was seen walking to a nearby store to buy food and hair dye. She also attended church with her parents and younger brother.

Jan Chwaszezewski, a 46-year-old plumber who lives across the street, said he had seen the woman outside of the house and visited the family in their home three times since they moved in two years ago but never suspected that something was amiss.

"Nothing pointed to this at all. There was no hint, no sign. The wife was always smiling," Chwaszezewski said.

The woman's story bears some similarities to the case of Austrian Josef Fritzl, who confessed to holding his daughter in a cellar for 24 years, repeatedly sexually abusing her and fathering her seven children.

The case in Poland involves a 45-year-old man identified only as Krzysztof B., in keeping with Polish privacy laws. Police detained him on Friday in the eastern city of Siedlce after his wife and daughter came forward with the allegations. The police believe he was trying to flee Poland.

"We have the hospital records of the children, and we will try to find them and carry out DNA tests" to determine their paternity, national police spokesman Mariusz Sokolowski told The Associated Press on Tuesday.

The woman told police that her father raped her repeatedly while keeping her captive in a room with no door handles. Krzysztof B.'s wife, identified only as Teresa B., corroborated the account, police said.

The case has been handed over to prosecutors who are now conducting the investigation, regional police spokesman Jacek Dobrzynski said.

The man was being investigated on several counts of sexual assault of a minor, incest and armed assault, said prosecutor Miroslaw Zoch in Siemiatycze. He cautioned, however, that it is "too early" to say whether the man fathered the two boys.

"We must first verify the evidence gathered by the police," he said.

Adam Kozub, a spokesman for the investigating prosecutors, said they have questioned the man and his brother, who is also a suspect in the case.

"It is a very disturbing story, but also a very delicate one because the victim is further suffering from the huge interest in her story," Kozub said.

Sokolowski said the woman did have limited contact with the outside world, including visits to hospitals to give birth to her sons, unlike Fritzl's captives, who officials said were locked in an underground cell.

"The main problem was the extreme psychological pressure she was under, the intimidation," Sokolowski said. "We are also looking for people who might have known about the situation."

Krzysztof B. is being held pending the outcome of the investigation.