A top Chinese leader under scrutiny amid China's biggest political scandal in years called for Communist Party unity in a prominent essay published Tuesday that shows his authority holding despite the investigation.

The editorial signed by Zhou Yongkang in the ruling party's main newspaper, People's Daily, urges the party's legal organs to closely follow policies set by President Hu Jintao.

"Let us unify even more closely around the party center with comrade Hu Jintao as general secretary," the essay says.

Replete with party jargon, the essay repeatedly mentions Hu's signature "scientific development" doctrine setting a course for rapid social and economic development under strict Communist Party rule.

Zhou, the party's security boss and its No. 9 ranking official, wields enormous influence over the police and paramilitary forces charged with maintaining internal stability at a time of growing unrest over corruption and uneven development.

Yet his authority has come under questions about his close association with former party official Bo Xilai, who was toppled over a scandal involving his wife's alleged participation in the murder of a British businessman.

While unlikely to face charges or be forced to resign, Zhou risks seeing his influence diminish sharply ahead of the nation's coming transition to younger leaders.

Bo has been dismissed as party boss of the sprawling western metropolis of Chongqing and was earlier this month suspended from the party's powerful Politburo. Bo's wife, Gu Kailai, and a household aide have been named as suspects in the murder of Neil Haywood, with whom the family maintained a close personal and professional relationship that later soured.

The case, and the unprecedentedly public manner in which it has evolved, has deeply embarrassed a party leadership obsessed with its image and whose inner working remain shrouded in secrecy.

It has also stirred new questions about the party's future, just months before this fall's once-in-a-generation appointment of new leaders.