COLUMBUS, Ohio (WCMH) — A pit bull dog named Bruno Marsten has died in mysterious circumstances, provoking an active animal cruelty investigation.

A spokesperson for Columbus Humane confirmed in an email to NBC4 that there is an ongoing investigation with the Cruelty Investigations Department regarding Bruno Marsten.

“Our investigation into Bruno’s death began on June 30th when we acquired Bruno’s remains for a necropsy evaluation. We are still waiting on the results of the necropsy to be able to determine cause of death,” the spokesperson said.

Columbus Humane, which is a partner agency with the Franklin County Dog Shelter & Adoption Center, said in a social media statement:

“As the agency actively investigating the circumstances around Bruno’s death, Columbus Humane can share only that our Humane Agents are awaiting autopsy results to determine the cause of death. Please know that we take all reports of animal cruelty seriously and we are reviewing the facts in this case carefully.”

Bruno Marsten was the longest-term resident, in and out of the shelter since April 2019. In October, Bruno was “back at the shelter” according to FCDS social media post featuring Bruno’s adoption video.

Bruno took a break from the dog shelter at Christmas, when a holiday sleepover video went up in late December. But Bruno still needed to be adopted to a good family.

The holiday sleepover video narrator played independently with his toys, and loved to have a ball thrown for him. He did well in the car, and loved to look out the window. Bruno began to settle into a routine in the second day, he listened well, and sat well to put on a harness. At 70lbs., Bruno was a goofball and tolerated a lot, never showed any signs of growling. “For how much he’s been through, he continues to be a positive and happy dog,” the video said.

A peaceful protest will be held on Sunday, July 18th from 11:00 a.m. to 1:00 p.m. on the corner of Morse Road and Tamarack in front of the Franklin County Dog Shelter in honor of Bruno, according to a social media post.