(CNN) — The family of LaShawn Thompson, an inmate who died in the Fulton County Jail last year, is demanding a criminal investigation into his death and for the facility to be closed and a new one to be built.

Family attorney Michael Harper, speaking at a news conference Thursday, blamed unsanitary conditions and complications from insect bites for Thompson’s death in September after three months in jail.

Holding up photos that purportedly show conditions in Thompson’s jail cell, Harper said, “The cell he was in was not fit for a diseased animal. This is inexcusable and it’s deplorable.”

The Fulton County Sheriff’s Office said in a statement, “The manner and cause of death was listed as undetermined by the county medical examiner. A full investigation was launched into the circumstances surrounding Mr. Thompson’s death.”

The results of that investigation would determine whether any criminal investigation is warranted, according to the statement.

Thompson had been in custody on a misdemeanor assault charge since June 2022 and was housed in the psychiatric wing of the jail because of his mental health issues, according to Harper.

Brad McCrae, Thompson’s brother, told reporters his sibling “didn’t deserve this.”

Thompson, 35, was from Winter Haven, Florida, but loved Atlanta, and went back and forth between the two cities. McCrae said his brother loved listening to music and cooking.

When asked by a reporter what he thought when he saw images of his brother’s body and the conditions of his cell, McCrae said, “It was heartbreaking because nobody should be seen like that. Nobody should see that. But the first thing that entered my mind was Emmett Till.”

The sheriff’s statement acknowledged the “dilapidated and rapidly eroding conditions” at the jail and said Fulton County Sheriff Patrick Labat continues to call for the building of a new jail.