The Grant County Sheriff’s Office is investigating the death of a 17-year-old girl last October.

Addison Rose Colomer of Mineral Point was found dead at a house at 301 W. Main St. in Montfort Oct. 1, according to her family.

Colomer’s sister, Maddie Deutsch, said Colomer “was found dead in someone else’s house of a supposed self-inflicted gun shot wound.”

“I just want people to know her name [and] what happened to her,” said Deutsch, whose family has set up a Justice for Addison Rose Facebook page.

Sheriff Craig Reukauf told WKOW-TV in Madison the cause of Colomer’s death was ruled undetermined by the Grant County Coroner’s Office.

Reukauf said the Sheriff’s Office wants to talk to anyone who had contact with Colomer before her death. Sheriff’s deputies responded to the call Oct. 1 around 2:35 a.m. Anyone with information is asked to contact Sheriff’s Sgt. Mark Schwarz, 607-723-2157.

Deutsch said her family is looking for anyone who was in Montfort between Sept. 30 at 6 p.m. and Oct. 1 at 3 a.m., or anyone who recognizes a dark-colored diesel flatbed truck or a green Ford F-150 pickup in that area that night.

“Addison came from a big, loud, loving family,” the Facebook page said. “She had parents, siblings, aunts, uncles, grandparents, and cousins who adored her — and a circle of friends so close they were family too. The kind of people who showed up, who knew her inside jokes, who loved her exactly as she was.

“And exactly as she was … was loud. Opinionated. She said what she thought and she wasn’t going to apologize for it. She had a fire in her that some people probably found a lot to handle … but underneath it, she had one of the biggest hearts of anyone we knew. She loved hard. She showed up for the people she cared about. She made people laugh even when she was the one having a rough day.

“She should be turning 18 surrounded by all of us, planning the next chapter of her life. Instead, we’re fighting for answers about how it ended before she got the chance.”

Colomer was found dead in a house in which three occupants are facing drug-related charges in Iowa County Circuit Court.

Ashton C. Johnson, 19, will make his first Grant County Circuit Court appearance July 13 on a felony charge of possession with intent of up to 200 grams THC.

Another person who lives at the house according to court records, Christopher J. Johnson, 44, will have a status conference in Iowa County Circuit Court July 14 on second- or subsequent-offense party to possession with intent of 5 to 10 grams heroin, second- or subsequent-offense party to possession with intent of 10 to 50 grams fentanyl, second- or subsequent-offense party to maintaining a drug trafficking place, party to possession of drug paraphernalia as a repeat offender, and two counts of felony bail jumping as a repeat offender.

Christopher Johnson also faces charges of felony retail theft of $500 to $5,000 and an additional felony bail jumping charge for a 2025 incident, and fourth-offense operating while intoxicated, operating after revocation (refusal), fourth-offense operating with a restricted controlled substance, two additional felony bail jumping charges and two misdemeanor bail jumping charges for a 2023 incident. His trial on the 2023 charges is scheduled for Aug. 13, with a pretrial conference July 14.

Another person listed in court records as living in the house, Linda M. Johnson, 72, made an initial Iowa County Circuit Court appearance Tuesday on a felony charge of threat to cause bodily harm to certain individuals involved with a court or legal system, for an incident April 17.