The 16-year-old boy who investigators say killed Breana Rouhselang, 17, has been charged with one count of murder and one count of feticide.

Aaron Trejo was ordered held without bond. He was arrested on Sunday, Dec. 9, and booked into the St. Joseph County Jail, where he remains in custody.

He is scheduled to appear before a St. Joseph County Superior Court Magistrate at 1 p.m. on Tuesday for his arraignment.

RELATED: Mishawaka High School student’s body found in dumpster, football player arrested for murder

According to court documents, Rouhselang went behind the house to talk to Trejo around 11 p.m. on Saturday. When she did not return, her parents reported her as missing to police.

Rouhselang’s mother went to Trejo’s home, looking for her daughter. Trejo told her that he had gone to meet her but she never showed up.

Police found glasses and a stocking cap that Rouhselang’s mother had described to police. They found blood on the cap, the court documents stated.

Police found more blood in the area which led police to the dumpster behind Pasquale Rulli’s restaurant in Mishawaka, where they found her body.

A black plastic bag had been placed over Rouhselang’s head and upper torso, according to the court documents.

Trejo told police he was the father of Rouhselang’s unborn child and that the two of them had gotten into a fight about the pregnancy and said that she had waited too long to get an abortion, the court documents stated.

He then admitted to stabbing her in her chest with a knife he took from his home, believing it would kill her quickly. He said he also brought the bag he placed over her body from home, as well, the court documents stated.

Trejo also told investigators he had been thinking about and planning to kill Rouhselang for about a week and had not told anybody. He told them that after he put her body in the dumpster, he walked to the river and threw her phone and the knife as far as he could into the water, the court documents stated.

According to the autopsy, Rouhselang died from multiple stab wounds and her scarf had been tied so tightly that strangulation was occurring before she died.

The autopsy also confirmed that she was pregnant.

Rouhselang and Trejo both attended Mishawaka High School and knew each other from the football team.

Mishawaka schools Superintendent Dean Speicher said some of the high school’s 1,500 students took part in a silent vigil Monday morning to honor Rouhselang.

Speicher said Rouhselang and Trejo had attended schools together since elementary grades, but he didn’t know any details about any relationship between them.

“They’ve known each other long before they came together — she as a manager and he as a football player — at Mishawaka High School,” he said.

Speicher said he didn’t know of any previous violence between the students.

“To our knowledge there were no signs, everything appeared to be very normal,” he said.

A GoFundMe campaign has been created to help Breana’s family pay for her funeral.

Donations are being accepted here.

The Associated Press contributed to this story