Authorities believe there was no foul play in the death of 22-year-old graduate student Eliotte Heinz, who was found dead Wednesday in the Mississippi River after vanishing over the weekend in La Crosse, Wisconsin.The La Crosse Police Department said Friday that, based on the preliminary autopsy results, it does not believe there was any criminal conduct related to Heinz's death.The Viterbo University student disappeared Sunday morning after a night out at bars with friends, Fox News Digital previously reported. Heinz was last seen walking along the Mississippi River waterfront at about 3:30 a.m. and was spotted on surveillance footage heading toward her apartment, which was less than a mile away.FISHERMAN FOUND WISCONSIN GRAD STUDENT FACE DOWN IN MISSISSIPPI RIVER DAYS AFTER MYSTERIOUS DISAPPEARANCEFour days into the search, a young fisherman found her body face down, wrapped in duckweed in the Mississippi River near Brownsville, Minnesota.It remains unclear how she ended up in the river.Final autopsy results will not be completed for several months, and investigators will continue to follow up on information, according to a statement from the police department. The investigation remains open.MISSING WISCONSIN GRAD STUDENT ELIOTTE HEINZS MOM SAYS CELLPHONE FOUND AS POLICE EYE TIMELINE: EXPERTThe University of Wisconsin River Watch, a program started in 2006 to prevent alcohol-related accidental drownings, reported that between 1997 and 2006, eight college students drowned in the Mississippi River as a result of excessive drinking.Heinz's family previously told Fox News Digital they are embarking on a path to healing."Eliotte is a beautiful person," the Heinz family wrote in a statement to Fox News Digital. "She was smart, funny, caring, and loved fiercely by us.We don't know why we were so blessed to have her as a daughter, or why we are unable to keep her.She is amazing and would have continued to amaze us.We are devastated that she is no longer with us.Our family will forever have a missing piece."We cannot thank our family, friends, the La Crosse community, Viterbo University, or the La Crosse PD enough for showing up for Eliotte. They were an amazing light in an incredibly dark space. Eliotte'swalk home is finished. Unfortunately, our family'swalk down this new hard path is just beginning. We love you Eliotte."The La Crosse County Sheriffs Office, Houston County Sheriffs Office, Jackson County Sheriffs Office, Vernon County Sheriffs Office, La Crescent Police Department, Wisconsin Department of Justice, Division of Criminal Investigations, Fort McCoy Fire and Rescue, U.S. Fish and Wildlife, La Crosse Fire Department, La Crosse Dive and Rescue, Wisconsin DNR, Minnesota DNR, La Crosse County Medical Examiner Office, Southern Minnesota Regional Medical Examiner's Office-Mayo Clinic and Viterbo University assisted in the investigation.Fox News Digital's Stepheny Price contributed to this report.