Stumped in their search for a motive, authorities at Virginia Tech have sent out a questionnaire asking students for any information they may have about gunman Seung-Hui Cho and his first victim.

A copy of the questionnaire obtained by The Associated Press asks students in the dorm where the rampage began if they had any interaction with Cho and whether they knew freshman Emily Hilscher, who was killed along with senior Ryan Clark in West Ambler Johnston Hall.

State police requested the questionnaire earlier this week, and the FBI asked resident advisers to help circulate the forms, said state police spokeswoman Corinne Geller. The questionnaires are voluntary, she said.

"This is another evidentiary tool," Geller said Friday. "It's just a way of reaching out to the student base."

Earlier this week, state police Superintendent Col. W. Steven Flaherty said police have been unable to determine why Cho began his attacks at the dormitory, and why Hilscher was the first victim.

Witnesses place Cho outside West Ambler Johnston shortly before 7:15 a.m., when he fired the two shots that killed Hilscher and Clark. It is not known how Cho entered the building.

Cho eventually killed 30 other people inside Norris Hall, before taking his own life in the worst mass shooting in modern U.S. history.

Most students said they did not mind filling out the questionnaire and hoped it would help investigators.

"Even though it is a little bit creepy for us to be having to fill this out, they should do whatever they can," said sophomore Kristina Ticknor, who lives on the floor where Cho killed Clark and Hilscher. "If anybody did see him around West AJ, or if anybody did see him the night before, and they're too scared to come out about it, this gives them the opportunity to do so."

A memorial of wilting flowers and rain-dampened letters of support still remained Friday outside Ambler Johnston, which houses nearly 1,300 students.

Ticknor said two white plywood walls have been put up to seal off Hilscher and Clark's rooms.

"I came back on Sunday, a week later, and it was really, really creepy to be back," Ticknor said. "But being back here in the community, everybody's doing so much to support each other, that it completely helps the healing process."

The questionnaire asks students six questions:

• Briefly describe your activities in and around Ambler Johnston Hall between the night of April 15 and April 16. Please include times.

• Have you seen any suspicious activity in or surrounding Ambler Johnston Hall that might pertain to the events of April 16? If so, please describe.

• Did you know Emily Hilscher? If you did, please describe the nature of your relationship.

• Have you ever seen Seung-Hui Cho in or surrounding Ambler Johnston Hall? If so, please describe.

• Did you know or have any interactions with Seung-Hui Cho? If so, please describe.

• Please provide any other additional information that may be helpful to the investigation.