The 29-year-old Westmoreland man accused of sexually assaulting his five-year-old sister and his two-year-old niece is now in police custody.
The man was held this morning.
The assault reportedly happened at their home last week in Negril.
The girls had to be hospitalised.
The mother of the five-year-old girl had said that she discovered that something was wrong while washing her daughter's underwear.
She said after talking with the child, she confronted her son who denied claims that he sexually assaulted his sister.
It was later discovered that the man's two-year-old niece had also been abused.
The woman is also the grandmother of the two-year-old.
She said she called the police and both children were taken to the station then to the Savanna-la-Mar Hospital where medical examinations confirmed that they were molested.
The accused was held by his older brother to be handed over to the police, but he managed to escape.