A cryptic note found in the search of Nhan L. Tran's bedroom moments after his arrest in a Feb. 11 shooting rampage that left a 9-year-old Oakdale boy dead could offer a pivotal clue to his state of mind, a potential issue in his upcoming trial.

Tran, 34, also told officers he began shooting randomly at cars passing along Hadley Avenue N. — a block over from where he lived with his parents in the 600 block of Guthrie Avenue N. — because they "had been following him around for a while and the persons driving the cars had been revving up their engines while parked in front of his house and waking him up," according to an affidavit filed in Washington County District Court requesting a search warrant.

The note, found on a desk, said "Random Kill, Fake Plates." In addition, the numbers "12/12/12" were found scrawled all over the bedroom's walls — the calendar oddity apparently referring to the end to the Mayan calendar, the document says, though the apocalyptic prediction also was linked to Dec. 21.

A receipt for the 9-millimeter handgun used in the shootings also was found, affirming that Tran had legally purchased the weapon.

Tran faces six felony counts stemming from the 20-minute rampage that began about 6:10 p.m. near the intersection of Hadley and 7th Street N., just south of the Rainbow Foods grocery store. The charges include second-degree murder with intent but not premeditation, second-degree murder without intent while committing a felony and second-degree attempted murder with intent but not premeditation.

Devin Aryal, a fourth-grader at Oakdale Elementary School, died after being shot in the head while riding home from day care with his mother, Melissa Aryal, who was shot in the arm.

Dml -, Star Tribune
Nhan L. Tran

Karen Knobloch lost part of a finger after she was wounded while driving with her three grandchildren.

Two other motorists narrowly avoided being struck by bullets.

The note on the desk could indicate that Tran had formed an intent to randomly kill the drivers, rather than acting impulsively, said Pete Orput, Washington County attorney. "I think the note is highly relevant — did he know what he was going to do?"

The scrawled dates on the wall could indicate mental illness leading to the inexplicable act of violence, Orput added, but that has yet to be determined.

"That doesn't stop there for us — you can be mentally ill and still commit a crime," he said.

Last month, Washington County District Judge Ellen Maas ordered a psychiatric evaluation for Tran and set his bail at $2 million.

He is being held in the Washington County jail.

Tran's next court hearing is March 25; prosecutors don't expect a trial until early next year.

Jim Anderson • 651-925-5039 Twitter: @StribJAnderson