KANSAS CITY, Mo. -- A Kansas City attorney on Thursday called for an FBI investigation of Jessup Carter's apparent suicide this week in the Jackson County Jail.
Attorney Henry Service said there needs to be accountability at the jail.
"That's outrageous, it's unacceptable. That's their job, that's their function to keep these prisoners safe and available to the court, and if they're failing at their basic responsibilities, someone has to take a serious, long look at what's going on down there," Service said.
Court records show Carter was likely a key witness in the murder trial of his half-brother, Kylr Yust.
Yust is accused of killing Jessica Runions and Kara Kopetsky in Cass County, Missouri.
Court records show that Carter was with Yust when Runions' SUV was found torched on Sept. 10, 2016. Later that day, both Carter and Yust were pulled over in Henry County.
"There's no excuse for a prisoner, especially one like this, to be in a position where they can take their own life," Service said.
Carter was in jail on arson charges stemming from a July 2018 fire in eastern Kansas City.
In a statement, Jackson County Department of Corrections Director Diana Turner said there is an internal investigation into Carter's death, which is standard protocol.
“We care about the welfare of all of those who are in our custody, so it’s heartbreaking for all department staff when someone takes their own life,” Turner wrote.
"Our thoughts and prayers are with the deceased’s loved ones during this difficult time,” she added.
In a Facebook post , Carter's mom, under a picture of her son, wrote, "My heart's so broken and I just keep thinking, crying and praying."
41 Action News Reporter Andres Gutierrez spoke with Carter last year about the case against his brother and his concern for the Kopetsky and Runions families.
"We want them to feel better at night that he's finally put away. I'm not okay and my family is not okay with anything that he did," Carter said in October 2017 .
Service, a former prosecutor, said Yust would have had the right to confront Carter in court as a material or key witness.
But with Carter's death, he said a judge may allow a recording of Carter or a detective who interviewed him to testify to what he said.
"Depending on the information that he would have given to the prosecutors and testified to in court, it could be devastating to their case," Service said.
A spokeswoman for the Runions family said that despite Carter's death, she's still confident in the case against Yust.
Carter's apparent suicide is also the latest problem in a series of issues at the Jackson County Jail.
Multiple former corrections officers have pleaded guilty in federal court to smuggling cellphones and cigarettes into the jail for inmates.
There's also an ongoing federal class action lawsuit against the jail claiming atrocious living conditions, such as raw sewage and black mold.