(CNN) -- Three people are dead, including a gunman who opened fire in a courthouse in Wilmington, Delaware, Monday morning, Delaware State Police said.
Two Capitol Police officers were wounded in the gunfight, but their injuries aren't life threatening because they were wearing bulletproof vests, police said.
The man entered the lobby of at the New Castle County Courthouse around 8 a.m. and began shooting, said State Police Sgt. Paul Shavack.
He acted alone, Shavack said, and the shooting was not an act of terrorism.
The two who are dead are women, but Shavack declined to give details about them.
News reports said the gunman's estranged wife was among the victims, but Shavack said he could not confirm that a family member was involved. He described the shooter as white and between the ages of 50 and 60.
Police said it's unclear how the gunman died. They are investigating whether he killed himself or police killed him.
Jose Beltran, a Court of Common Pleas worker, told the News Journal in Wilmington that he was walking into the courthouse lobby when he heard shots.
"I saw two shots," he said. "I saw people going on the ground so I just made a U-turn and ran out of the building. After that I don't know what happened."
Thomas Warren told the newspaper that as he approached the courthouse entrance to report for jury duty, he saw what appeared to be the body of a man lying on his stomach.
Local and federal authorities, including agents from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, responded.
The courthouse was evacuated and police did a floor-by-floor search of the 12-story building to make sure there was only the single gunman and there were no more threats, Shavack said.
The shooting came on the day the police chief of Wilmington was in Philadelphia to attend a roundtable discussion about gun safety. Vice President Joe Biden, law enforcement officials and members of Congress were attending. Biden, who served as a senator from Delaware for many years, acknowledged Monday's shooting.
"Wilmington has been dealing with a murder rate that exceeds any number a city of its size should be dealing with," he said.
The city's population is 71,305, according to 2011 census figures. There were 23 murders in the city that year, according to FBI statistics.
Monday afternoon Joseph R. "Beau" Biden, Delaware's Attorney General and the son of the vice president, spoke at a news conference about the shooting.
"This is not a random act of violence," he said, but stems for a long custody dispute that "has lasted in our court system for many years."
Biden and other law enforcement authorities would not publicly name the shooter or the deceased, saying that they wanted to continue with the process of their investigation first.
The officers who survived the shooting were treated and released from a hospital, police chief William Jopp said.
The New Castle County Courthouse will be closed Tuesday.
CNN's Jake Carpenter, Stephanie Gallman and Laura Ly contributed to this report.