The two men police arrested last week in connection to the Bronx house explosion that killed a city firefighter could soon face more serious charges. NY1's Rocco Vertuccio filed the following report.

It was an emotional day Tuesday for the FDNY. Dozens of firefighters packed a court hearing in Bronx criminal court for the two suspects arrested in connection with last week's house explosion in the Kingsbridge section of the Bronx.

FDNY Deputy Chief Michael Fahy was killed when he was hit by flying debris while directing traffic at the scene. He was a 17-year veteran of the department. His funeral was last weekend.

"These are the guys that caused the death of a great person," said FDNY Battalion Chief Daniel O'Donnell. "I have no real feelings toward them, it's just, we want to be here to support the family, really."

Investigators say there was a marijuana grow lab in the house at West 234th Street, and a gas leak sparked the explosion.

The two men police arrested last week, 32-year-old Garivaldi Castillo and 34-year-old Julio Salcedo, were charged with marijuana possession. At their court hearing Tuesday, the suspects decided not to testify before a grand jury. Prosecutors will now try to indict them on more serious charges, first-degree assault for Fahy's death and second-degree assault for another firefighter who was hurt in the blast.

"It's a sad day to be here like this. We'd rather be at City Hall listening to them get a medal or something," O'Donnell said.

Both suspects are due back in court in two weeks, when they will likely be arraigned on those assault charges.