WARNING: Story details sexual abuse which may be distressing for some readers

Austrian sex offender Josef Fritzl, who locked his daughter Elizabeth in a cellar for 24 years and sexually abused her and fathered seven children with her, has claimed he is a “good guy” in a disturbing new book.

The 87-year-old monster released a book titled Die Abgruende des Josef F (The Abysses of Josef F), where he claims to have a number of illegitimate children abroad resulting from “dozens of sexual affairs” during business trips.

According to Austrian and German media, one excerpt reveals that Fritz believes he’s a “good person” despite his horrific crimes against his children.

“In reality, I’m a good person”, and states that the former electrical engineer cannot understand why his wife Rosemarie broke off contact with him.

In 2009 he was sentenced to life imprisonment for incest, rape, coercion, false imprisonment, enslavement and for the negligent homicide of one of his infant sons.

Fritzl’s daughter disappeared in 1984 at age 18, re-emerging in 2008 from the dungeon-like basement chamber in the town of Amstetten where her father had kept her captive. Fritzl built the basement himself.

The abuse resulted in the birth of seven children – three of whom remained in captivity with their mother.

One died at the hands of Fritzl, a matter of days after being born. He disposed of the body in an incinerator.

The other three were brought up Fritzl and his wife, Rosemarie.

Fritzl told his wife that Elizabeth had run away to join a cult, that the children belonged to their daughter, and had been left on their doorstep as she was unable to care for them.

In the book, he also claims he receives “hundreds of letters” from women he claims are in love with him.

He also detailed how he wants to spend the last years of his life in freedom.

Describing his prison life, he said he avoids walking in the yard “because there are a few prisoners just waiting to be able to beat me up”.

He reportedly has just one friend in prison, a prostitute murderer who Fritzl describes as a “helpful, nice guy” because he cooks for him regularly.