It was a Fourth of July dream: houseboats anchored in a cove, smaller craft nearby, music playing, people swimming or relaxing on inflatable rafts.

But what health experts call the “silent killer” — carbon monoxide — turned the scene Sunday at Perry Lake into a tragedy.

The Jefferson County Sheriff’s Office said Tuesday a woman who drowned Sunday at Perry Lake initially was overcome by carbon monoxide fumes that built up in the air from several boat engines running.

Another woman had to be pulled from the water and revived by cardiopulmonary resuscitation after she lost consciousness, and a teenage girl overcome by fumes was transported to St. Francis Health Center in Topeka, said Sgt. Jerry Greene, a sheriff’s detective.

Shortly before 8 p.m., divers from the Sheriff’s Office recovered the body of Melissa Kennedy, 34, Holton. Divers had been in the water about 30 minutes, Greene said.

About 10 houseboats and several smaller boats with engines running were idling in the cove in the Slough Creek area, forming a crescent. A generator powering a karaoke machine also was running, Greene said.

Carbon monoxide fumes built up low over the water, he said. “There was no breeze; it was just trapped.”

Kennedy and another woman were seen in the water seemingly floating on their backs, Greene said. A man became concerned, however, when he saw a riderless Wave Runner tethered to a boat bump one of the women in the head and she did not respond.

“At that point he knew something was wrong,” Greene said. “He pulled the woman out of the water.”

The woman, identified as Jenny Dick, 31, Topeka, was not breathing but was revived, Greene said. She refused an ambulance ride to the hospital, he said. Meanwhile a search was on for the second woman, identified as Kennedy.

“I’m told about 20 guys jumped off the boats, but they just couldn’t find her,” Greene said.

The third victim, Rebecca Williams, 13, Kansas City, Mo., was found unconscious and unresponsive on a swimming platform of a boat, Greene said. Tuesday night a hospital spokeswoman said there was no patient there by that name.

An autopsy showed the carbon monoxide level in Kennedy’s blood was 45 percent, Greene said.

“That’s enough to make you unconscious, and if you are in the water, you drown,” Greene said.