The drowning death of a 12-year-old boy at a York County campground's pool was accidental, the coroner's office said Friday.

The York County Coroner's Office released its determination after an autopsy to investigate the cause of Pau Khai's death.

Khai was a member of a Westminster Presbyterian Church group on a retreat at Summit Grove Camp & Conference Center in New Freedom on Wednesday.

Following an afternoon swimming activity, which ran from 3:30 p.m. to 6 p.m., church chaperones reportedly cleared the campground's pool and noticed Khai was missing, according to a statement posted to Facebook by Summit staff.

The campground said chaperones reported having checked the pool and searched the area with no success. A 911 call was made, Southern York Regional police responded and officers joined in the search.

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Police said Thursday that Khai was reported missing around 4 p.m. and was last seen wearing a white t-shirt and swim trunks.

The search ran eight or 10 hours, starting in the late afternoon and into the early morning hours. According to the county coroner's office, Khai’s body was found in the pool around 2 a.m.

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“Pau’s whereabouts and what specifically transpired between 6 p.m. on June 29th and 2 a.m. on June 30th is unknown and the focus on the ongoing police investigation,” campground staff stated.

Messages left with the Lancaster-based church were not returned Friday.

— Reach Aimee Ambrose at aambrose@yorkdispatch.com or on Twitter at @aimee_TYD.