A judge set $3 million bail Tuesday for a Billings man accused of killing his estranged wife and leaving her body in a vehicle in a remote Big Horn County field.
Tanner Grove, 32, did not speak during his eight-minute arraignment from the Yellowstone County jail, even as Judge David Carter asked him direct questions through video call from the courtroom.
In light of Grove’s silence, Carter entered a not guilty plea for him to three felony charges: deliberate homicide, burglary and tampering with evidence.
The bond amount was three times higher than the $1 million requested by Yellowstone County Deputy Prosecutor Sabrina Curry, who called Grove “an extreme flight risk” who was a “clear and present danger to the community.”
Grove is accused of killing 35-year-old Shawna Hart, also known as Shawna Grove, who had a restraining order against him since October 2025.
Prosecutors said in court documents that Grove went to Hart’s residence on April 22, and witnesses told police she appeared to get into his vehicle willingly, leaving her children and cell phone inside the residence.
Police learned this information on April 23 from a friend of Hart’s, and on the next day, April 24, Hart’s son reported to police that she was still missing. He showed screen shots of text messages between Hart and Grove that were “turbulent,” according to court documents. Police saw from phone records that her last call was made at 11:17 a.m. April 22, and they issued a missing person advisory and began a massive search.
Police got a tip he was driving with another woman, and officers pulled over her vehicle. He allegedly gave a false name, then tried to run before he was apprehended, according to court documents.
The woman driving Hart told police he had showed up to her house with multiple stolen items, including a bicycle and tools, that he sold at a pawn shop. Grove later told a friend in a recorded jailhouse call that he was selling the items in an effort to get enough money to leave town because he feared he was going to prison.
Curry, the prosecutor, also told the judge Grove allegedly asked the friend to sell valuable property he had in Roundup to fund the flight.
Police found Grove’s vehicle in the early evening of April 24 in a farmyard at the intersection of South Fly Creek and Highway 87 East outside of Hardin. Inside, they found Hart’s body with a “penetrating wound on the left side of her head from a projectile,” according to court documents.
Video surveillance later showed the vehicle had arrived at the farmyard around 12:10 a.m. April 23, and a man stepped out. He removed a bicycle from the trunk, ate food from a brown paper bag on the hood, then pedaled away on the bike.
“These offenses show a calculating plan to kill (Hart), dispose of her body, and dispose of the vehicle,” Curry said.
At the time of his arrest, Grove had two warrants for his arrest from Billings Municipal Court: one related to a previous sentencing on an assault committed against Hart, and a second on charges that he allegedly pointed a gun at Hart’s children on March 29.
Grove was released from jail, where he was serving his sentence for the assault against Hart, 13 days before the murder.
Grove’s next scheduled court appearance is 8 a.m. June 15.
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