U.S. Justice Department and the FBI on Friday started inquiries to determine whether the murder of three Muslim students in North Carolina earlier this week was a hate crime.

President Barack Obama described the case as "brutal and outrageous," after Turkish President Tayyip Erdogan criticized him for his initial silence about the incident.

"No one in the United States of America should ever be targeted because of who they are, what they look like, or how they worship," Obama said in a statement on Friday.

Deah Shaddy Barakat, his wife Yusor Mohammad Abu-Salha and her sister Razan Mohammad Abu-Salha were found dead in their home on Tuesday in Chapel Hill, North Carolina. One of their neighbors, a middle-aged white man, was later arrested and charged with three counts of first-degree murder.

Police said preliminary inquiries indicated that the murder was probably motivated by a neighbor dispute over parking place. However, the victims' families insisted it was a hate crime and called on an FBI inquiry into the case.

Meanwhile, a fire broke out in a vacant building in an Islamic center early Friday in southeast Houston. Investigators said they were still determining whether it was an arson attack.