MINNEAPOLIS (AP) — The man charged with killing the top Democrat in the Minnesota House and her husband, and wounding a state senator and his wife, pleaded not guilty Thursday in federal court.

Vance Boelter, 58, of Green Isle, Minnesota, was indicted July 15 on six counts of murder, stalking and firearms violations. The murder charges could carry the federal death penalty, though prosecutors say that decision is several months away.

One of Boelter’s attorneys entered the plea on Boelter’s behalf during Thursday’s arraignment. Boelter was in the courtroom and wore an orange sweatshirt and yellow pants. He spoke briefly to affirm that he understood the charges and thanked the judge.

When prosecutors announced the indictment, they released a rambling handwritten letter they say Boelter wrote to FBI Director Kash Patel in which he confessed to the June 14 shootings of Melissa Hortman and her husband, Mark. However, the letter doesn’t make clear why he targeted the Hortmans or Sen. John Hoffman and his wife, Yvette, who survived.

Boelter’s federal defender, Manny Atwal, said at the time that the weighty charges did not come as a surprise, but she has not commented on the substance of the allegations or any defense strategies.

Thursday’s hearing before U.S. Magistrate Judge Dulce Foster also served as a case management conference in which Foster issued a revised schedule with various deadlines, though no trial date has been set.