UPDATE 1-China Tibet policymaker probed for state secret leak

(Adds dissident sentenced to jail, paragraph 10)

By Ben Blanchard and Benjamin Kang Lim

BEIJING, Nov 22 (Reuters) - A key Chinese Communist Party policymaker for Tibet is being investigated after her computer was hacked and classified documents stolen related to Beijing's talks with the Dalai Lama's envoys, sources said on Saturday.

Bi Hua, 53 and a Han Chinese, was asked to step down recently as director of the No. 7 bureau of the Party's United Front Work Department, two independent sources with knowledge of the case said, requesting anonymity for fear of repercussions.

"She is under investigation," one source told Reuters. "But she insists she has done nothing wrong."

Her computer was hacked by unknown individuals, and classified documents stolen, the sources said.

It enabled the Dalai Lama's representatives to have a heads-up as to Beijing's bottom line towards talks.

"It was a major leak," a second source said.

The embarrassing security lapse came as Tibetan exiles gathered for a special meeting to discuss their future, a gathering that could possibly challenge the Dalai Lama's moderate line towards Beijing.