Police tape blocks the path to the Capitol in Denver on Monday after a suspect was shot when he apparently made threats against Gov. Bill Ritter.

Denver ? A man carrying a gun and declaring “I am the emperor” was shot and killed Monday outside the offices of Gov. Bill Ritter by a state trooper, a spokesman said. Ritter was in his office but was not injured.

The unidentified man refused orders to drop his gun, spokesman Evan Dreyer said. Four or five shots were heard, but authorities would not say how many times the patrolman fired.

The gunman did not fire his weapon, police spokesman Sonny Jackson said.

Before he was shot by a member of the governor’s security detail, the gunman said, “I am the emperor and I’m here to take over state government,” Dreyer said.

The man initially walked into the vestibule of Ritter’s office and was being escorted out when he produced the gun and refused orders to put it down, Jackson said. The shooting occurred about 2 p.m. in a hall outside the governor’s offices on the first floor of the Capitol.

Ritter said he was in the office with 10 or 11 people and heard shots, but he would not say how close he was to the gunman. Some of his staff members witnessed the shooting, he said.

Investigators did not know the man’s name or his motive, Jackson said. He declined to discuss the gunman’s statement but said it was considered threatening.

The gunman had at least two confrontations with the governor’s security guards in the moments before the shooting, Jackson said, giving no details. There had been no prior specific threats against the governor, authorities said.

The Capitol has no metal detectors. They are usually installed temporarily during the governor’s annual State of the State address in January but then are removed.

Metal detectors were installed at the Capitol after the Sept. 11, 2001, terrorist attacks but were removed the following July after lawmakers objected to making it more difficult for the public to visit.

State Rep. Edward Casso said he saw the gunman after the shooting and described him as being in his 30s or 40s, dressed in a white shirt and dark slacks.

Authorities roped off the area where the man was shot, and an ambulance and eight police cars converged on the building’s north entrance.

An hour after the shooting, state troopers and police – some carrying automatic weapons – ordered the Capitol evacuated and did a room-by-room search, not saying what they were looking for.

Police in the Denver suburb of Northglenn said the man may have rented a tuxedo from a formal wear shop Monday morning. Jackson said the man appeared to be wearing a dark suit.

Tobie Locke, a bridal manager at the Mister Neat’s shop, said a man came in around 10 a.m. asking to rent a tuxedo and when asked the occasion said, “Today’s the day of the emperor’s reign.”

She noticed he was carrying a gun and a knife and called police immediately after he left the shop in an SUV, about three hours before the shooting. The man did not say where he was going.

“It’s a good possibility that it’s the same guy,” said Northglenn police Sgt. Steve Garrow.

The man left with a standard black tuxedo, a black bow tie and a black vest.

“He was very nervous and sweating a lot and breathing very heavy,” Locke said. “I had the impression he was going to hurt somebody.”

Starting today, all visitors to the Capitol will be required to enter through a single entrance and pass through a metal detector, Ritter said. It wasn’t clear how long the requirement would be in place.