Six people were killed in Tucson today by a shooter who appears to have had as his primary target U.S. Rep. Gabrielle Giffords. She was critically injured by a gunshot to the head.

Judge John Roll

Among those killed was U.S. District Court Chief Judge John Roll. We will have more on Judge Roll, but for now, here is a statement from the United States Courts for the Ninth Circuit:

Federal Judiciary Mourns Death of Chief District Judge John M. Roll of Arizona

SAN FRANCISCO – The federal judiciary was in mourning after learning of the death today of Chief District Judge John M. Roll of the United States District Court for the District of Arizona. Judge Roll was among six people believe killed at political event in Tucson. He was 63.

Flags will be lowered to half mast at many federal courthouses in memory of Judge Roll, who had his chambers in Tucson. He had been attending an event organized by Rep. Gabrielle Giffords of Tucson, who also was shot and critically wounded. As many as 16 more people were injured in the shooting.

“All of us in the Ninth Circuit court family were shocked and terribly saddened to learn today of the death of Chief District Judge John M. Roll. Our hearts go out to his family and to all of the families of those killed or injured in this senseless tragedy,” said Chief Judge Alex Kozinski of the U.S. Court of Appeals for the Ninth Circuit.

“Judge Roll was a widely respected jurist, a strong and able leader of his court, and a kind, courteous and sincere gentleman. He worked tirelessly to improve the delivery of justice to the people of Arizona. He was always upbeat, optimistic, enthusiastic and positive in his outlook. He touched many lives and will be sorely missed by all who knew him – colleagues, court staff, members of the bar.”

Ninth Circuit Judge Mary M. Schroeder of Phoenix, a former chief judge of the circuit, said Judge Roll was respected and love in both his professional and personal life.

“He was famous for being able to say so many genuinely nice things about people without having to consult notes, for he so genuinely loved people and had such a remarkable mind,” Judge Schroeder said. “Judge Roll will be greatly missed and will continue to provide inspiration for the generations of lawyers and judges who were fortunate enough to know him.”

Judge Raner C. Collins of Tucson, who will assume the role of chief district judge for the Arizona court, said he and his colleagues were shocked and deeply saddened.

“How do you explain such a senseless tragedy? Our hearts really go out to the family,” Judge Collins said.

The Arizona court is authorized 12 judgeships and now has two vacancies.

Nominated by President George H.W. Bush, Judge Roll came onto the federal bench in 1991. He was elevated to chief judge in 2006. Under his leadership, the Arizona court has sought additional judges and other resources to better manage a growing caseload. One of two border courts in the Ninth Circuit, drug smuggling and illegal immigration predominate its criminal caseload.

Born in Pittsburgh, Penn., Judge Roll received his B.A. in 1969 from the University of Arizona and J.D. in 1972 from the UA College of Law. He also received a LL.M. in 1990 from the University of Virginia School of Law.

Prior to coming onto the federal bench, he had served as a judge of the Pima County Superior Court 1988 to 1991, and on the Arizona Court of Appeals, 1986 to 1987. He also had served as an assistant U.S. attorney for Arizona, 1980 to 1987, and as a deputy county attorney for Pima County, 1978 to 1979.

Judge Roll is survived by his wife, Maureen, three sons and five grandchildren.