Berlin (CNN) -- A German man who pleaded guilty to sexually abusing his daughter, stepdaughter and stepson was sentenced to more than 14 years in prison Tuesday, a court official said.
The man, identified only as Detlef S., was accused of hundreds of incidents of sexual abuse of his children between autumn 1987 and summer 2010.
He pleaded guilty on Monday to all charges, said Alexander Walter, Koblenz state court spokesman. He was convicted of severe sexual abuse of children in 42 cases, rape, sexual abuse of wards and sponsoring rape, Walter said.
He was sentenced to 14 and a half years in prison, and will stay in preventive custody after that because the court feared he would commit further criminal acts, Walter said. Preventive custody usually means that a person who has served their sentence remains behind bars but receives extra privileges.
Detlef S. admitted last month when the trial opened that he was the father of multiple children with his stepdaughter.
He was charged with the sexual abuse of dependents and facilitating the sexual abuse of minors.
He was also accused of bringing his underage stepdaughter and his daughter to men who paid for sex with them on multiple occasions.
The first allegations of abuse came more than a decade ago, in 1998, but there was no medical evidence to support the claims then, Germany's youth welfare office said in a statement when the trial opened February 15.
Two stepsons leveled fresh accusations in 2002, saying the defendant was abusing his biological daughter, then 11. Police began an investigation but found no medical evidence and dropped the case, the statement said.
The daughter denied having been abused, the welfare office said.
Two men other men are facing trial on charges of sexual assault in connection with the case. A third man suspected of abusing the children has died, Walter said.
The stepdaughter gave evidence against Detlef S., the court spokesman said. It was unclear at what age she gave birth to the children.
DNA test results introduced in court gave a "99.999%" certainty that the defendant is the father of her children, Walter said.
Seven of the stepdaughter's eight children survived infancy, he said. He did not know the cause of death of the eighth.
The sexual assaults took place in the defendant's home, in woods nearby and in various apartments near where the family lived, prosecutors alleged.
Only two of the 350 charges are related to the stepson, Walter said.
CNN's Diana Magnay contributed to this report.