The 24-year-old man killed after shooting two Palm Bay police officers and fatally wounding his grandfather Sunday was driving a car packed with a cache of handguns and other weapons that may have been part of a bigger, planned attack, the Palm Bay police chief said.

The car, seized by police after the shootout that left gunman Brandon Kapas dead, was tracked to its owners, retired Catholic priest Robert Hoeffner and his sister, Sally Hoeffner. Both were shot to death by Kapas earlier in their northwest Palm Bay home, Police Chief Mariano Augello said at a Monday press conference.

“It’s unknown what his intentions were, showing up with an arsenal of weapons,” Augello said.

“Our officers' actions yesterday prevented something even more tragic from happening.”

Palm Bay patrol officers were called about 2:07 p.m. Sunday to the Kapas family home, Florida Today reports.

Augello said officers arrived about 2:19 p.m. and immediately met with an uncle who told them Kapas, his nephew, was in the home being disruptive during a family birthday celebration. The uncle told police that Kapas was possibly armed. At that moment, Kapas stepped out of the home and quickly began walking away "as Palm Bay officers attempted to talk with him,” Augello said. 

An officer tased Kapas and got into a brief struggle before Kapas reached for his handgun and fired at police, the chief said. Officers Stephen Ball and Nicholas Franze were shot, one in the arm and the other in the leg. 

The gunman's grandfather, William Kapas Sr., attempted to intervene but was shot and killed by the suspect, Augello said.

“The grandfather was trying to help,” the chief said. 

Officers returned fire in response, killing Kapas.

Auguello spent time Monday visiting the wounded officers, one of whom was recovering from surgery and the other, who was set to be released.