The 7-month-old girl who was allegedly murdered by her 14-year-old brother died from suffocation and was bitten by bugs after her death, according to preliminary information from a medical examiner cited by prosecutors on Monday.
The teen, Jonathan Aguilac, has been charged as an adult with first-degree murder in the death of Larissa Yanes. At a court hearing in Rockville, a judge ordered that the teen be held without bond and be transferred from a jail for adults to a juvenile detention facility.
On Thursday night, the children's mother went to work and left Larissa in her brother's care. After his mother returned to her Silver Spring apartment on Friday morning, she discovered Larissa unresponsive, police said.
When police interviewed the teen, he said he beat his baby sister. He said that he then put his hands on his sister's nose and mouth, restricting her breathing, because Larissa was crying. Then, he walked around the apartment with the infant in his arms and put her in a car seat in the living room, according to a charging document.
Detectives saw Larissa at a hospital and noticed several "suspicious" injuries on her body, according to the document. Although police had thought that a beating caused these injuries, prosecutors said in court Monday that, according to the medical examiner, these injuries were caused by post-mortem bug bites.
After the hearing, Montgomery County State's Attorney John McCarthy called the bug bites "an additionally sad aspect" of the incident. Police are continuing to investigate the incident, and the autopsy has yet to be completed, McCarthy said.
A law enforcement source familiar with the probe said authorities are investigating living conditions of the apartment and whether the teenager may have been abused himself and his treatment of his sister may have been "learned behavior."
Aguilac had to be charged initially as an adult because he was charged with first-degree murder. The defense will be requesting that a study be done to determine whether the case should stay in adult court or be moved to juvenile court. A preliminary decision about where the case will be tried could come as early as Feb. 22, McCarthy said.
The teen's public defender, Mary Siegfried, said her client went to school every day and took care of Larissa and a 3-year-old sister every night while his mother works.
"He is not a problem at school," she said. The teen appeared at the hearing via a closed-circuit television.
Montgomery County Public Schools spokesman Dana Tofig said Aguilac is an eighth-grader at Francis Scott Key Middle School. Counselors were at the school Monday to help students who may have been upset by the incident.