Texas investigators on Wednesday were looking to find out why a man went on a shooting rampage that left six people dead and three others wounded a day earlier, and ended when the suspect was captured after a shootout in Austin.

Shane James, 34, was charged early on Wednesday with four counts of capital murder and held without bond, according to records at the Travis County jail.

No other charges were immediately listed, but interim Austin Police Chief Robin Henderson said at a press conference that more charges were pending and that James was connected to all the shootings.

Investigators were still uncertain about a motive for the shootings.

“The nature of the relationship between the suspect and any of the victims is unknown,” Henderson said.

The shootings began on Tuesday morning, and extended throughout the day at multiple scenes near Austin and in the San Antonio area about 80 miles (129 km) away, but police did not initially connect the incidents, Henderson said.

The first shootings in Austin were on the grounds of a high school, where a school officer encountered an armed suspect and sustained wounds that were not life-threatening.

Around noon, police responded to a report of a double homicide of a man and woman in South Austin, police said, and that shooting was later connected to the suspect.

At about 5 p.m., police responded to a report of a bicyclist who was shot and wounded, Henderson said.

Some two hours later, police received a call about a burglary in progress, also in Austin, and discovered an armed man in the backyard of the home, Henderson said.

Police exchanged gunfire and an officer was shot and wounded. Two bodies were found in the house.

The suspect sped away in a car, chased by officers, until he crashed the vehicle and was arrested, Henderson said.

Later, at an address associated with the suspect near San Antonio, two bodies were discovered. Henderson said the two are believed to have been murdered before the rampage in Austin began.

It was not immediately clear how police connected all the crime scenes. A spokesperson for Austin Police Department was not immediately available to Reuters for more information.