A 14-year-old White Oak boy has been charged with first-degree murder after admitting he smothered his infant sister.

Montgomery County Police said that Johnathan Aguiluc killed his 7-month-old sister Larissa Yanes while she was under his care. Police received a call at about 6:26 a.m. on Friday morning reporting a pediatric injury. When police arrived at an apartment on the 11600 block of Lockwood Drive, they found Larissa unresponsive.