As the death toll from the Beltway sniper mounted, Robert Holmes felt the ache in his gut grow worse.
The crimes unfolded 2,700 miles away, but Holmes, a Tacoma, Wash., auto mechanic, felt intimately linked. He believed that the killer was a friend of his.
"I was hoping it wasn't him, but at the same time, I thought it was," said Holmes, 46, speaking publicly for the first time.
The day after the ninth victim, an FBI analyst, was killed in a Home Depot parking lot in Fairfax County, Va., Holmes called the FBI office in Tacoma. He said he knew the identity of the serial sniper -- his close friend John Muhammad.
Holmes knew that his phone call to the FBI would possibly save the lives of potential victims and lead to the execution of his friend of 17 years.
"It's a double-edged sword: He's a friend, so it puts it on a personal level, but there was no other option than to call," Holmes said. "It's a matter of doing the right thing."
"John knew I was the only one who knew it was him," he went on. "No one knew what I knew."
Holmes' knowledge included that Muhammad had fallen apart when he lost custody of his three children the year before, that his ex-wife, Mildred, lived on the East Coast, that Muhammad was a marksman, and that he had discussed equipping a long-distance rifle with an illegal silencer.
Holmes said Muhammad had told him, "Can you imagine the damage you could do if you could shoot with a silencer?"
Holmes' call and subsequent interview with FBI agents here helped authorities identify the suspected snipers, gather evidence and ultimately make two arrests.
According to federal law enforcement sources familiar with the sniper investigation, Holmes' call was the break they needed.
"As far as a lot of us are concerned, the guy's an American hero," said a source who asked not to be identified.
Muhammad and John Lee Malvo could face the death penalty if found guilty of the murders. "I was the beginning of the end for John," Holmes said sadly.
In lengthy, high-profile investigations such as the Beltway sniper case, where scores of police spend thousands of hours and deploy the latest technology, it is not unusual that a friend or family member provides key evidence that leads to an arrest.
The perplexing Unabomber case was finally cracked when the killer's brother turned him in. David Kaczynski realized that his brother, Theodore, had written the anti-technology tracts linked to the mail bombings that killed three people and injured 23.
About 65,000 tips were called in to the Beltway sniper task-force hotline. In the Seattle area, the FBI office got at least 20 sniper tips. Holmes' information about Muhammad rose to the top.
The two men had met in 1985 when they were in the Army, stationed at the Fort Lewis. Their friendship continued when Muhammad moved to the Tacoma area after serving in Germany and the Persian Gulf War. Each operated his own auto-mechanic business. They talked frequently.
Holmes is 6-feet-4, a burly, soft-spoken former Golden Gloves boxer. He and Muhammad had mutual interests -- love of their children, women and cars. Holmes' friends describe him as generous, willing to help someone who was down and out.
When Muhammad lost three of his children in a custody battle with his ex-wife in 2001, he started to spiral downward.
"The catalyst was he lost his kids," Holmes said. "His kids were his life. There was no other reason for him to live."
After the serial sniper's fifth victim died Oct. 3, at an intersection in Washington, D.C., Holmes told a friend on the phone, "I know that's John doing the East Coast killings."
The friend was dismissive.
By the time the ninth person died, at the Home Depot on Oct. 14, Holmes could no longer be silent. He called the FBI's Tacoma office Oct. 15 and asked to meet with an agent, saying he knew the identity of the sniper. A secretary said he needed an appointment and took a message.
When the FBI did not call back later that day, Holmes called the sniper task-force hotline. He was told to wait for the local FBI to call him back.
An FBI agent called Holmes back one or two days later. Holmes told him that Muhammad had served in the Army, owned guns and knew how to shoot, and that he was unhinged by losing his children to his ex-wife who lived on the East Coast.
Meanwhile, the public and authorities looked for a mentally disturbed white man and a white van lurking in D.C.-area neighborhoods and racing away on interstate highways.
While Holmes waited for the FBI to act on his information, he learned that the sniper had wounded a woman and killed another in the Maryland area.
Then, on Oct. 17, one of the snipers -- police say it was Malvo -- called the sniper task force and revealed clues that led police to a killing outside a liquor store in Montgomery, Ala.
By Oct. 20, the FBI matched a latent fingerprint from the store shooting to an Immigration and Naturalization Service fingerprint of Malvo, an illegal immigrant who had lived in Bellingham, Wash., with Muhammad.
It had been five days since Holmes had called the FBI.
On Oct. 22, FBI agents met with Holmes. They showed him a security-camera photo of a man and asked whether it was Muhammad. Holmes said yes.
Then the agents played a tape-recorded message from someone claiming to be the sniper and asked whether it was Muhammad's voice.
Holmes said no, but that it could be Muhammad's surrogate son, Malvo, with whom he had been traveling. Holmes also told agents that Muhammad might be traveling by bus or sleeping in a car.
During the three-hour interview, Holmes told the FBI that the pair stayed at his house frequently. During one visit, Muhammad and Malvo showed him an assault rifle with a scope and a book on how to make a sound suppressor. Also, Muhammad fired a gun into a tree trunk in the back yard of his home, Holmes said.
On Oct. 23, the FBI searched Holmes' back yard, cut out a section of the trunk with bullet fragments, and shipped it to its crime lab.
There is a $500,000 reward in the sniper case, to be dispersed after the first trial. The Tacoma auto mechanic may end up with a share.
"Holmes' information, alone, would have eventually gotten us there," a U.S. Justice Department source said.