The suburban Chicago landlord accused of stabbing a 6-year-old Palestinian American boy to death and badly wounding his mother was ordered held behind bars Monday while federal authorities opened a hate crimes investigation into what they say was a deadly anti-Muslim attack.

Dressed in an orange prison-issued jumpsuit, his hair disheveled, 71-year-old Joseph Czuba answered “yes sir” to the judge but otherwise sat quietly in a Will County courtroom where he was formally charged with three counts of murder, one count of attempted murder, two counts of aggravated battery and two counts of committing a hate crime.

Investigators said the deadly attack that resulted in the death of Wadea Al-Fayoume was linked to the ongoing conflict between Israel and Hamas in the Middle East.