Soules, who was portrayed as a wholesome country boy looking for love on season 19 of the ABC reality show, was behind the wheel of a pickup truck that rear-ended a tractor in northern Iowa near Aurora on Monday night, the Iowa State Patrol said.
The crash caused the tractor to roll and go into a ditch on one side of the road, while Soules' truck went into a ditch on the other side, the patrol said. The tractor driver was taken to a hospital, where he was pronounced dead. The patrol identified him as 66-year-old Kenneth Mosher, a farmer from Aurora.
Soules wasn't injured in the accident and left the area before emergency responders arrived, the Buchanan County Sheriff's Office said. He was arrested later at his home in Arlington, which is about 10 miles (16 kilometers) north of Aurora and 75 miles (120 kilometers) north of Iowa City.
Authorities said someone had called 911 to report the crash, but they didn't release the identity of the caller or audio of the call. Investigators spoke to multiple witnesses and determined that Soules caused the crash and fled, according to a complaint, which doesn't name the witnesses.
Police audio of the incident obtained by the Des Moines Register shows that a deputy told a dispatcher Soules "took off" in a red truck while Mosher was unconscious in his vehicle.
Alcohol was found at the scene, and investigators are trying to determine whose it was, said Sheriff Bill Wolgram. Court records show that Soules has had some driving infractions in the past, including a 2006 conviction for operating while intoxicated.
Soules, 35, was arrested about five hours after the crash and then booked into the Buchanan County Jail on a charge of leaving the scene of a fatal accident, which carries a penalty of up to five years in prison. He was released around midday on $10,000 bond, and will be required to surrender his passport and wear an electronic monitoring ankle bracelet until his trial, jail officials said.
The sheriff's office said the crash remains under investigation and additional charges could be filed.
Soules' lawyers, Sean and Molly Spellman, didn't immediately reply to messages seeking comment. His spokesman, Stan Rosenfield, issued a statement saying Soules "was devastated" to learn that Mosher died.
"His thoughts and prayers are with Mr. Mosher's family," said Rosenfield, who declined to comment further.
Soules first drew national attention as a participant in "The Bachelorette" in 2014, when he tried to win the affections of star Andi Dorfman but was passed over. A fan favorite, ABC had him back as "The Bachelor" the following year. His appearance drew attention to farming life and some of the struggles facing rural Iowa. He proposed to Chicago fertility nurse Whitney Bischoff at the end of his season, but their relationship ended shortly after the show.
Soules has since served as a spokesman for various agricultural interests and worked in farm real estate and investing.
The crash comes as Gov. Terry Branstad and lawmakers have expressed alarm about a rising number of deaths on Iowa roadways caused by intoxicated and distracted drivers. Branstad last week signed laws allowing officers to pull over drivers for texting while driving, increasing the penalties for texting-related vehicular homicides, and creating a statewide sobriety and drug monitoring program for intoxicated drivers.