Elisabeth. On 29 April, it was announced that DNA evidence confirmed Fritzl as the biological father of his daughter's children. His defence lawyer, Rudolf Mayer, said that although the DNA test proved incest, evidence was still needed for the allegations of rape and enslavement. In their 1 May daily press conference, Austrian police said that Fritzl had forced Elisabeth to write a letter the previous year indicating that he may have been planning to release her and the children. The letter said that she wanted to come home but "it's not possible yet." Police believe Fritzl was planning to pretend to have rescued his daughter from her fictitious cult. Police spokesman Franz Polzer said police planned to interview at least 100 people who had lived as tenants in the Fritzl apartment building in the previous 24 years. Cell The Fritzl property in Amstetten is a building dating from around 1890. A newer building was added after 1978 when Fritzl applied for a building permit for an "extension with basement." In 1983, building inspectors visited the site and verified that the new extension had been built according to the dimensions specified on the permit. Fritzl had illegally enlarged the room by excavating space for a much larger basement, concealed by walls. Around 1981 or 1982, according to his statement, Fritzl started to turn this hidden cellar into a prison cell and installed a washbasin, toilet, bed, hot plate, and refrigerator. In 1983, he added more space by creating a passageway to a pre-existing basement area under the old part of the property, of which only he knew. The concealed cellar had a corridor, a storage area, and three small open cells, connected by narrow passageways; and a basic cooking area and bathroom facilities, followed by two sleeping areas, which were equipped with two beds each. It covered an area of approximately . The cell had two access points: a hinged door that weighed which is thought to have become unusable over the years because of its weight, and a metal door, reinforced with concrete and on steel rails that weighed and measured high and wide. It was located behind a shelf in Fritzl's basement workshop, protected by an electronic code entered using a remote control unit. In order to reach this door, five locking basement rooms had to be crossed. To get to the area where Elisabeth and her children were