Derrickson was found shot and killed on June 17 in Mishawaka.

Nashawn Stephens, 18, has been charged with murder and a firearm enhancement.

Kyndall Dickerson, 19, has been charged with murder, conspiracy to commit murder and assisting a criminal.

On June 17 at 11:15 p.m., Stephens burst into Dickerson's bedroom while she was with Derrickson, beat, then dragged Derrickson out of the bedroom and shot him in front of the apartment building, reports said.

The day of the murder, Dickerson told police she didn't know the attacker. After multiple interviews with police, she finally admitted she knew Stephens was the man who entered her bedroom and attacked Derrickson, according to the probable cause affidavit.

Dickerson told police she is occasionally sex partners with Derrickson, and also occasionally with Stephens as well.

Dickerson spoke with police and admitted she was engaging in sexual relations with Derrickson when Stephens entered the bedroom and began pistol whipping Derrickson with a handgun, according to the probable cause affidavit.

The investigation also revealed a witness confirmed driving Stephens to the apartment complex on the day of the murder, reports said.

Police also said the day of the murder, each time Dickerson spoke with Derrickson that day, she then contacted Stephens, reports said.

In one of their communications, Dickerson told Stephens she would leave a key under the mat for him, reports said.

Stephens was arrested on August 26. Dickerson was taken into custody on Monday.