Bismarck police call son a suspect in slaying

FARGO — Bismarck police have arrested the 47-year-old son of a slain Bismarck woman here on suspicion of stealing her motor vehicle, and Bismarck Deputy Chief Dan Donlin said Thursday the man is considered a suspect in his mother’s homicide.

Dean Roy Grenstiner of Bismarck was arrested in Fargo on Wednesday by Bismarck police and is being held in the Cass County Jail pending a transfer to the jail in Burleigh County.

Grenstiner is the son of 83-year-old Ann Grenstiner, whose body was found in her home in Bismarck on Tuesday afternoon. Her vehicle, a silver 2012 Honda CR-V, was found Wednesday morning in Fargo behind Duffy’s Tavern.

Dean Grenstiner was charged in Burleigh County District Court on Thursday with a count of felony theft in connection to the stolen SUV.

Donlin said police believe they can prove the son stole his mother’s vehicle, and he confirmed he is a suspect in the homicide investigation.

But detectives are still pursuing other leads related to the case as well, he said.

“We always have to keep an open mind to whether anyone else was involved or not — that’s what we hope the investigation will show,” Donlin said.

“We need to continue as an investigation unit in this case to investigate all leads on a broad perspective,” he added.

Prompted by public tips to look for Dean Grenstiner in Fargo-Moorhead, Bismarck police and local authorities were able to quickly find the suspect on Wednesday, Donlin said.

Donlin said he didn’t know why Grenstiner came to the Fargo area.

An autopsy was performed Wednesday on Ann Grenstiner, which Donlin said confirmed her death as a homicide. The woman’s body had apparently sustained heavy trauma in the incident, he said.

Police have brought the woman’s vehicle back to Bismarck and will soon examine it for evidence related to the case.

According to online court records, Dean Grenstiner has two felony convictions in Burleigh County.

He was convicted in 1997 of gross sexual imposition, ordered to serve a four-year prison term and register as a sex offender.

In 2007, he was convicted of being an accomplice to the theft of property. He served nearly 18 months in prison for that conviction.

Sam Benshoof is a reporter

at The Forum of Fargo-Moorhead, which is owned by Forum Communications Co.

Tags: news, crime, murder