A teacher's assistant is on trial for allegedly shooting and killing her high school sweetheart in the home they shared.

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Police in Griffin, Georgia say Mary Katherine Higdon, 24, shot Steven Freeman, 23, in the chest at the house on Sunnybrook Drive in 2018.

In court Thursday, Freeman's friends took the stand and said the two had a toxic relationship.

Investigators said Higdon, who most recently worked as a preschool teacher’s assistant at St. George’s Episcopal School in Griffin, told officers the gun went off accidentally. She said she was in the back room of their home and as she handed the gun to Freeman, it went off.

But police told WSB-TV the evidence says otherwise.

Freeman's best friend, Thomas Skinner, took the stand first and described his friend to the jury.

"Steven was a warm, loving guy, a country boy, hard worker," Skinner said.

Skinner told the jury his friend's relationship with Higdon started off fine but quickly turned toxic.

"At first, I really liked her, I did. Things in that relationship I could see started getting more toxic, fighting and arguing, verbally fighting," Skinner said.

When Freeman tried to leave, his best friend told the jury Higdon would drag him back into the relationship.

"Mary Katherine texted Steven something along the lines of wanting to kill herself and if Steven didn't move back in, she would kill herself,” Skinner said.

After Skinner's testimony, prosecutors called another one of Freeman's friends to the stand. Alijah Varela, who also worked with Freeman, told the jury Higdon would brag about how she knew how to use a gun and would also call and text Freeman nonstop while he was at work.

"He would just have his phone sitting down, and you could just see it off the hook, upwards of 20 calls within the time it took us to get the truck loaded. Steven always drove, and it would just be sitting there ringing off the hook," Varela said.

Varela said Freeman had a big heart.

"I wasn't brought up to say, 'I love you,' every single time you get off the phone, but every time Steven left or was going somewhere, he would always tell you, 'I love you,'" Varela said.

The defense says Freeman drank, did drugs and controlled Higdon, but Freeman's friends told the jury it was the other way around.

His co-worker told the jury how Freeman would describe her to him.

"She was always angry. Satan," Skinner said.

Court resumes Friday and will last until 5 p.m.

The prosecution will hear from more witnesses, and then the defense will begin its case.