"Right from the beginning, she was 100 percent positive it was the guy," Blair said.
The department has gotten calls in the past from people who thought they recognized a fugitive from television, but none ever panned out, he said.
Blair said he called the show's hotline and played the go-between to see if the information the woman provided checked out with authorities on the case.
Going back and forth, he grew more convinced every time she would tell him something that she couldn't have learned from the show, he said.
It was sewn up when she brought a snapshot to the barracks that matched FBI photos, Blair said.
Usually, police investigating a televised case are in the "America's Most Wanted" studio to check out the validity of tips to the show's hotline, Molnar said.
That was true of Grubb's case, aired as a one minute, 15 second-long "all points bulletin" during the show's 11th season premiere on Saturday, he said.
Grubb was portrayed as a "serial bank robber," charged or suspected in a total of 27 bank robberies up and down the East Coast, Molnar said.
Every job was pulled the same way, with a note instructing the teller to put $20 bills in a bag and threatening that he or she would be shot if it contained a dye pouch or an alarm was set off, he said.
"He never tried to conceal his identity. We had tons of video from surveillance cameras," Molnar said.
Less than seven hours from the end of the show, Grubb's trailer was surrounded by a slew of police, Blair said.
Officers included members of the West Virginia State Police Special Response Team and other state troopers, agents from the FBI and U.S. Marshal's Service and a Delaware state trooper, he said.
"What we were looking at here was a potentially dangerous situation," said Blair, who said the goal was to minimize the danger to officers and Grubb, who lived alone in the rented trailer.
Grubb was alone and was arrested without incident , he said.
Once Grubb's identity was confirmed, the "America's Most Wanted" crew hopped the news chopper from WTTG - Fox Channel 5 in Washington, D.C. - to get to West Virginia and make the "grab shot" when Grubb opened his door, Molnar said.
"We basically pulled him out of bed," he said.
Grubb is wanted on federal arrest warrants for bank robbery in Maryland, Pennsylvania, Delaware, Tennessee and South Carolina, Blair said.
He is also wanted on a parole violation by federal authorities in Ohio, he said.
He was not wanted in West Virginia, Blair said.
Grubb wasn't well-known on rural Loop Road, where residents were shocked to hear they'd had a federal fugitive as a neighbor.
"That is something to find. I would have never imagined," said Michael Combs, 20, who said he is new to the area and doesn't know his neighbors.
Even if he knew him, he doesn't watch "America's Most Wanted," so he wouldn't have known Grubb was sought by police, he said.
"It's pretty wild," said a 29-year-old neighbor, who said she was scared to think her two children might have been in danger when they played outside.
While she didn't recognize his name, it's possible she might have recognized his face if she saw the program.
A loyal "America's Most Wanted viewer," she said she missed it because she and her boyfriend were busy painting.
"It's a real good show. We try to watch it every week," she said.
Though not as well-publicized as this caller's assistance, tips regularly help West Virginia State Police solve local cases, Blair said.
"Without the community, we wouldn't be able to function. We depend on them for information," he said.
Grubb was taken to Eastern Regional Jail in Martinsburg to await an appearance in federal court this morning, Blair said.