ELKHART, Ind. (AP) — A police standoff with an armed man ended after more than 18 hours when state troopers entered a northern Indiana home, took him into custody and found a 2-year-old boy dead inside, police said.

The 37-year-old man was being held at the Elkhart County Jail pending a charging decision by the county prosecutor’s office, Indiana State Police said. The Elkhart County Homicide Unit and state police were investigating.

Troopers who entered the home Sunday afternoon found the 2-year-old boy dead while a 4-year-old girl who was also found inside was treated and released to a relative.

State police said the standoff began about 9 p.m. Saturday when Elkhart County Sheriff’s deputies were asked to conduct a welfare check on a man and his two children at a home west of Elkhart.

Deputies were unable to locate the man but learned that he was inside the home, was armed and had “threatened to harm his children and law enforcement,” state police said in a news release.

Early Sunday, an Elkhart SWAT team tried to contact the man, who police said refused to leave and discharged a firearm before barricading himself inside. Officers made numerous attempts to contact the man “with little success” before troopers entered the home, police said.