A group of Minnesota friends who were on their way to the Kentucky Derby for a bachelor party have cancelled their trip after making a grisly discovery.

Law enforcement officials were called Thursday night to a Shopko parking lot just off Highway 61 in Winona after the men discovered a body in a rented motorhome. The Winona Daily News reports the body was found in an exterior cargo bin on the RV. Winona Police Chief Paul Bostrack told the newspaper that the motorhome has been impounded and is being treated as a crime scene. He said the body has been taken to Mayo Clinic for an autopsy and formal identification.

KSTP reports the body was discovered by men who had rented the vehicle for a bachelor party. The station said that the men, who are in their mid-20s, had rented the RV from a private party in Anoka County before heading for Louisville.

Dan Trainor told the station that friends in Minneapolis picked up the RV on Thursday, then drove to Rochester to pick up Trainor. Trainor was driving the RV as the group traveled to Winona to pick up another friend. They pulled over in the parking lot of the closed Shopko store to check on a foul odor. Trainor said he saw the body when he looked in a storage compartment that was only accessible from the outside.

"I opened it up and I saw two legs and they're bruised or decomposing," Trainor said."I had never seen a dead body before."

Jake Wanek of Minneapolis also saw the body and described it to the Star Tribune as a man who “didn’t look fresh. Let’s put it that way.”

The newspaper reported that all of the men attending the bachelor party are either from Winona or attended college there. Wanek said that their bags are still in the motor home, described as more than 30 feet long with a bedroom, kitchen and bathroom.

Wanek said the bachelor party has been revised. The men now plan to stay in Winona Friday night and watch the Minnesota Wild playoff game. On Saturday, they will watch the Kentucky Derby at Canterbury Park instead.

ABCNewspapers reports that investigators have not revealed the cause and manner of death.

A press release from the Anoka County Sheriff’s Office says that the Anoka and Winona police departments, Minnesota Bureau of Criminal Apprehension and Anoka County Sheriff's Office are investigating.