MILWAUKEE (AP) — A 14-year-old boy accused of killing two teenage brothers during a failed home robbery in suburban Milwaukee told investigators he fired his gun after getting scared during a struggle with one of the victims, according to charging documents filed Wednesday.

Investigators allege the boy and a 13-year-old friend planned to steal money and marijuana from the West Ellis home on Sunday. The younger boy said the pair left with nothing, the Milwaukee District Attorney’s Office said in court documents.

Killed in the shootings were 17-year-old Trajan “Tra” Edwards and 19-year-old Croshian “CJ” Edwards. The documents say the 14-year-old suspect knew the victims and had been stopping by their house to hang out for the last three months.

The 14-year-old boy is charged as an adult with two counts of first-degree reckless homicide and attempted armed robbery. Court records don’t list a defense attorney, and a working publicly listed phone number for his family couldn’t be found. The 13-year-old is expected to be charged as a juvenile, prosecutors said.

The younger boy told a police detective the pair had planned the robbery for a week. He said he had a hammer to “smash” Trajan’s fingers or “bust his knee caps a little” in case he “did not want to talk,” according to court documents. He said his friend had a firearm.

The 14-year-old told investigators he had not planned on hurting anyone, but that after he pulled out his gun he got into a struggle with Trajan. He said he got “scared and sick and did not want to die,” according to the charging documents. The 13-year-old boy said he ran away after Trajan was shot. The older suspect also ran, shooting Croshian in the kitchen as he fled.

If convicted of all charges, the 14-year-old could face up to 150 years in prison.