The inside of a boat where a fatal carbon monoxide exposure occurred on the St. Croix River contained a detector that wasn’t turned on.

The Department of Natural Resources released information Thursday, June 29, from a preliminary report outlining circumstances of the incident discovered along the river in the town of St. Joseph, where a woman was found dead and two men were found sickened.

“Working carbon monoxide detectors would have prevented this, in addition to adequate ventilation,” DNR Recreational Safety Warden Mark Little said.

The June 25 incident, which officials said appeared to be an accidental carbon monoxide exposure, left 24-year-old Glenwood City resident Ashley Speer dead.

The boat’s owner, 25-year-old Hastings resident Justin M. Roskos, remained in critical condition Wednesday at Hennepin County Medical Center, according to a spokeswoman. A third man found on the boat, Hayden L. Johnson, 27, River Falls, was taken to HCMC where he was initially listed in stable condition, but was later released, Little said.

A DNR report states Roskos had purchased the boat two days before the trio went out on the river the evening of June 24. Little said officials don’t yet know where the boat entered the river or if it had a destination.

It appeared the boat, a 34-foot 1989 Wellcraft, struck a buoy while heading south from Stillwater; a cable was found wrapped around both propellers, according to the report. Little said it’s not clear yet whether the cable entanglement could be an indication of whether or not the boat was under an operator’s control.

The boat was beached at High Line Beach overnight until being discovered on June 25 by authorities who responded to a welfare check.

The DNR report states the boat’s camper enclosure was found up and closed, while all its hatches and ports were also in the closed position. A generator was running, according to the DNR.

A carbon monoxide detector was found in the off position not far from where Speer was located.

Those factors, Little said, “were significant issues.”

A certified generator technician did not find anything mechanically wrong with the device, according to the DNR.

Little said the investigation could take several more weeks.