A 12-year-old schoolgirl whose body was found dumped in thick undergrowth beside a canal had been raped, beaten and strangled.
A team of 80 officers spent yesterday combing the banks of the Royal Canal at Porterstown, near Blanchardstown in west Dublin, and carrying out house-to-house inquiries.
A large area running from the canal to Michaela's family home at the Village in Porterstown was cordoned off. Her bicycle was found a short distance away yesterday morning and that location was also sealed off.
Last night, gardai maintained a presence outside the family's semi-detached house while the road remained closed to all except residents.
A 19-year-old man was being questioned by gardai last night on suspicion of being involved in a serious assault after presenting himself at Blanchardstown station on Saturday. He was accompanied by his father.
It is believed that the schoolgirl, who had her first day at Luttrellstown Community College on Thursday, had been hanging around with older teenagers and young adults in recent times and may have been vulnerable.
She spent Friday with friends and then went home. At midnight, she told her parents she was going out on her bicycle and would be back soon.
Gardai believe Michaela had arranged to meet a particular individual. When she failed to return home her parents raised the alarm.