The message was written in red ink on the back of a flier with a piece of clear tape attached. The handwriting was sloppy.

"Bomb will go off if you open the door," it said. The word "Bomb" was underlined.

The makeshift sign, on a door inside Norris Hall, caught the attention of Virginia Tech associate engineering professor Janis Terpenny as she started her morning on April 16.

Terpenny grabbed the sign and opened the door, despite the warning. Moments later, she handed it to janitor Pamela Tickle, who decided to take it to a supervisor. As the two women discussed the sign, Seung-Hui Cho was nearby, preparing to launch his murderous rampage.

Tickle said she remembers passing Cho twice in a Norris hallway just moments before taking the sign from Terpenny.

Terpenny thought the sign was another empty bomb threat, one of several recently on Virginia Tech's campus. Then she noticed that a set of doors leading outside the building was chained shut. Terpenny and Tickle now believe that Cho, a Virginia Tech senior, posted the handwritten note to discourage people from entering the hallway from the stairwell and interrupting him as he chained and padlocked the doors.

Virginia State Police confirmed Friday that they found a note after the shootings on the same table in the same second-floor room where Tickle says she left it.

"We did find a note in Norris Hall, a threatening note, but we're still trying to determine how it's connected," said state police Lt. Tim Lyon. "We've not at this time linked it to him."

Lyon also said that investigators have not linked Cho to any of the bomb threats received before April 16.

Cho chained shut the three main exits in the building on April 16 before he fatally shot 30 people inside and then himself. Two other students died after they were shot in a dorm across campus a couple of hours earlier.

Tickle, 26, said she was running a dust mop down the hallway when she passed someone she now knows was Cho: an Asian man with a burgundy hat and cargo pants who walked briskly toward the exit, which is beside the door leading to the stairwell. At that point, the exit had not been chained, she said.

"He was kind of noisy," Tickle recalled. "You could hear stuff jingling."

She wondered why he was in such a hurry and figured maybe he needed to turn in a paper in one of the offices along the hallway. The shootings took place in another hallway on the same floor where classes were being held.

Tickle said she rounded a corner into the hallway where gunfire would erupt a few minutes later, and noticed a black backpack on the floor beside a water fountain. Police have confirmed that Cho carried a backpack with him into Norris Hall.

She waited to see if someone would claim it, but she saw only one other man walk out of a bathroom and stroll, hands in his pockets, toward one of the classrooms.

Tickle ran the mop back down the hallway and saw the man in the cargo pants hurry past her again.

"He didn't even look at me," Tickle said. "He just looked very serious. I guess he just had his mind concentrated on what he was going to do."

As she reached the end of the hallway, she saw a student try unsuccessfully to exit the building through the chained doors.

"He was kind of like, 'What's going on?' " Tickle said of the student.

About that time, Terpenny walked down from the third floor and took the note that was taped to the door inside the stairwell on the second floor, and walked through the door.

Terpenny didn't take the threat seriously at first, but Tickle read the note carefully, at least twice. She said she remembers exactly what it said. Tickle started thinking that the note might not be a joke. "I said, 'That door's chained, and we don't chain the doors,' " Tickle said. "I'm going to call my supervisor."

Terpenny said she went back upstairs to see if she could find out what was going on. Tickle said she heard the first gunshots as she walked toward a closet to get her phone to call her boss.

The student who moments earlier had tried to exit the building through the chained doors, walked back toward Tickle after hearing the shots, she said.

"We were just looking at each other like what was going on," she said.

They went into a second-floor lounge where another student was lying on a couch, cutting class. He was supposed to be down the other hall in one of the classrooms, Tickle said.

"Thank the Lord ... he didn't go," she said.

Tickle and the two students locked themselves inside.

At one point, Tickle said she looked out a window and saw another janitor, Gene Cole, running outside.

Cole had taken an elevator to the second floor to look for Tickle after the shooting started, he has told The Roanoke Times. When the elevator doors opened, he saw a body on the floor and thought it was Tickle.

Suddenly, Cole said, he saw a man pointing a gun at him. He escaped safely.

Tickle said she and the two students came out of the lounge when they heard police outside the room. She said she left the bomb note on a table in the room and mentioned it to police.

Lyon said he is unaware of any other threatening notes found in the building.

Terpenny said that she and several others were evacuated safely from the third floor.

Tickle had cleaned Norris Hall five days a week ever since she started working at Tech more than three years ago. Now she works in Burruss Hall.

Tickle, of Giles County, said she misses the people she had come to know in Norris. Along with the pleasant memories, however, Tickle said she will remember how Cho looked as he marched down the hall to murder 30 students and teachers.

"I can still picture his face as he walked by me," Tickle said. "And just the look he had in his eyes."