A man barged into the Arkansas Democratic headquarters and opened fire today, fatally shooting the state party chairman before speeding off in his pickup. Police later shot and killed the suspect after a 30-mile chase.

Police said they don’t know the motive for the 51-year-old suspect, whose name has not been released. However, they said moments after the shooting, he pointed a handgun at the building manager at the nearby the Arkansas Baptist headquarters. He told the manager “I lost my job,” a Baptist convention official, Dan Jordan, said.

Chairman Bill Gwatney died four hour after the shooting. The 48-year-old former state senator had been planning to travel to the Democratic National Convention later this month as a Hillary Clinton superdelegate.

Mrs. Clinton and her husband, President Bill Clinton, issued a statement calling Gwatney “not only a strong chairman of Arkansas’ Democratic Party, but he is also a cherished friend and confidante.”

Witnesses said the gunman entered the party offices shortly before noon and said he wanted to see Gwatney.

“He said he was interested in volunteering, but that was obviously a lie,” a 17-year-old party volunteer, Sam Higginbotham, said. He said the man then pushed past employees to reach the chairman’s office, where he fired three times.

After the suspect avoided spike strips and a roadblock along U.S. 167 near Sheridan, police rammed his car, spinning it, the Grant County sheriff, Lance Huey, said. He got out of his truck and began shooting, and state police and sheriff’s deputies fired back, striking him several times, he said.

The state Capitol was locked down for about an hour until police got word the gunman had been captured, Arkansas State Capitol police Sargent Charlie Brice said.

Governor Mike Beebe, a Democrat who served with Gwatney in the state Senate, had been on a flight to Springdale at northwestern Arkansas. He returned to Little Rock and joined an impromptu vigil at University Hospital after what he called a “shocking and senseless attack.” Gwatney had been Mr. Beebe’s finance chairman during the governor’s 2006 campaign.

“Arkansas has lost a great son, and I have lost a great friend. There is deep pain in Arkansas tonight because of the sheer number of people who knew, respected and loved Bill Gwatney,” Mr. Beebe said.

State Rep. Janet Johnson started to cry when she talked about Gwatney.

“This is like something you would see in New York or Pennsylvania or California, but not here,” Ms. Johnson said.

The executive director of the Republican Party of Arkansas, Karen Ray, sent her workers home early “out of an abundance of caution.”

“Our hearts go out to everyone at the Democratic headquarters. What a tragedy,” Ms. Ray said. “This is just a very upsetting, troubling and scary thing for our staff as well.”

House Majority Leader Steve Harrelson was at the state Capitol for a news conference on crime and that he didn’t know of anyone who would want to harm Gwatney.

“You never think of something like this happening here in Arkansas,” said Mr. Harrelson.

A sales clerk at a flower shop across street from the party headquarters, Sarah Lee, said that around noon Gwatney’s secretary ran into the shop and asked someone to call 911.

Ms. Lee said the secretary told her the man had come into the party’s office and asked to speak with Gwatney. When the secretary said she wouldn’t allow him to meet with Gwatney, the man went into his office and shot him, Ms. Lee said.

Last November, a distraught man wearing what appeared to be a bomb walked into a Clinton campaign office in New Hampshire and demanded to speak to the candidate about access to mental health care. A hostage drama dragged on for nearly six hours until he peacefully surrendered.

The confrontation brought Mrs. Clinton’s campaign to a standstill just five weeks before the New Hampshire primary. Security for her was increased as a precaution. She said she did not know the suspect.