GREENWOOD, Ark. (AP) — Two students, including a 5-year-old, were among the three people killed Wednesday in an early morning house fire in western Arkansas, authorities said.

Greenwood Police said in a Facebook post that they responded to the fire shortly after midnight. Police said Daniel Isaiah Arrington, 18, Vivian Medrano, 5, and their mother, Wendy Medrano, 46, died in the fire. Police did not identify a fourth person who was critically injured and was hospitalized.

The cause of the fire was under investigation, and the victims' bodies had been sent to the state crime lab, police said.

Greenwood Public Schools earlier Wednesday had said two of the people killed in the fire were students. The district said it had arranged to make counselors available at each of its campuses.

“Our deepest sympathies go out to the families involved, as well as to our dedicated staff and students, as we navigate this sorrow together,” the school said in a statement.

Greenwood is located about 95 miles (155 kilometers) northwest of Little Rock.