Police and the city Medical Examiner are investigating the death of a human fetus that was born in a restroom Monday at Kapolei Regional Park.

Investigators estimated the age of the fetus, a female, at about 30 weeks.

They said a young woman who appeared to be in her late teens was complaining of stomach cramps and went to use the restroom just before 9 p.m. Monday. She gave birth there, police said.

The woman denied knowing she was pregnant, police said.

Bryan Cheplic, spokesman for the city Emergency Services Department, said paramedics were called to the park at 8:51 p.m. and took the woman to a hospital in serious condition.

The fetus was pronounced dead at 9:50 p.m., Cheplic said.