DALLAS — Police in the Texas Panhandle are investigating a minor drug allegation made against former NFL quarterback Ryan Leaf, who this week was placed on leave from his job as an assistant football coach at West Texas A&M.

Canyon police Chief Bobby Griffin says the investigation is in its preliminary stages, but confirmed the allegation was that Leaf obtained a controlled substance by fraudulent means.

"We are trying to determine whether anything like that happened," Griffin said. "There is not enough information or facts to say we have a crime being committed or not."

Leaf did not immediately respond to a message left by The Associated Press and Griffin said the police have not interviewed him.

"Some allegations have been made and some rumors are flying around. We've been asked ... to look into it," said Griffin, who declined to say why police began the investigation.

Leaf, a former Heisman Trophy finalist who led Washington State to the 1998 Rose Bowl, is the quarterbacks coach and men's golf coach at West Texas A&M in Canyon, about 20 miles southwest of Amarillo in the Texas Panhandle.

On Wednesday, West Texas A&M athletic director Michael McBroom said he and Leaf met Sunday and agreed the ex-quarterback should take a leave of absence. McBroom declined to say why Leaf is on leave and when or whether he would return.

This is Leaf's third season as quarterbacks coach at West Texas A&M, which is 9-1 heading into its final regular season game. Quarterback Keith Null has completed nearly 68 percent of his passes and has 36 touchdowns and 14 interceptions. The team's passing offense ranks first in the Lone Star Conference.

Leaf was taken second in the 1998 draft behind Peyton Manning. He retired after four seasons, better known for off-field outbursts than on-field play. He finished his career with 14 touchdowns and 36 interceptions.