The state conservation officer who fell from his boat and drowned on an eastern Minnesota lake in April wasn't wearing a life jacket, nor was the sheriff's deputy who was with him, said authorities, who used the disclosure Thursday as an opportunity to encourage boaters to wear the safety devices.

State law does not require adults to wear life jackets in watercraft, but the Department of Natural Resources (DNR) and the Pine County Sheriff's Office both have policies requiring their personnel to do so, the agencies said.

Conservation officer Eugene Wynn Jr., 43, died the night of April 19 after he and deputy Scott Grice were thrown from a boat into Cross Lake and went under water within a minute of responding to a call of something suspicious floating in the lake near Pine City.

Rescuers pulled Grice from the water, and he was treated and released. Wynn's body was found about 1:30 a.m. the next day following an intensive search.

The boat was equipped with two life jackets, the Sheriff's Office said. State law requires one life jacket for each person on board, whether a civilian or a law enforcement officer.

"Everybody [with the DNR] wears a life jacket when you are on or near the water," said agency spokesman Joe Albert, citing the policy.

Sheriff Jeff Nelson said his department's policy says its personnel "should be wearing safety devices and that includes life jackets."

"We strongly recommend that all people that are enjoying the natural resources in Pine County use all safety devices that are appropriate," a statement from the Sheriff's Office read. "That would include life jackets, helmets, seat belts, and tree stand safety harnesses. Accidents happen very quickly, even to the very well trained and experienced."

"The safety devices only work if people put them to use before an accident happens. In this case, the officers were thrown from the boat within a minute of being on the water and were not able to continue swimming within minutes."

Nearly three weeks after the incident, investigators say that what sent Wynn and Grice into the water remains a mystery.

Wynn accelerated the DNR boat from shore and then "suddenly made an abrupt left turn," Thursday's statement from the Sheriff's Office read. "The boat corrected, and both Wynn and Grice were thrown from the boat."

The boat continued on its course until it beached on the west side of Cross Lake. It traveled about 800 feet on the water and about 50 feet onto land.

The boat is owned by the Minnesota DNR and is a 2004 River Pro with an inboard jet drive.

Property owners on the lake reported seeing large chunks of ice on the surface until the following night, but "it is unknown if the evasive maneuver was related to debris on the lake," the statement continued. "No parties report hearing an impact while the boat was on the water."

Also, the Sheriff's Office added, a Coast Guard inspection of the boat found nothing that would have played a role in the men ending up in the water.