Police said Saturday they have questioned an employee of Samsung C&T Corp. for allegedly conducting an illegal surveillance on the chief of CJ Group, amid a growing feud over the family inheritance fight over Samsung, South Korea's biggest conglomerate.

The summons came as CJ Group sued the 42-year-old Samsung employee, identified only by his surname Kim, for suspicions of following its chairman Lee Jae-hyun late last month after the chairman's father filed an inheritance suit against the chief of Samsung Group, Lee Kun-hee.

In the suit filed in mid-February, the father of Jae-hyun, Lee Maeng-hee, who is the elder brother of the Samsung chief, demanded a large amount of stocks he claimed the Samsung head secretly had incorporated into his assets.

The lawsuit calls for the Samsung chief to return 8.24 million shares of Samsung Life Insurance Co., worth more than 700 billion won (US$625.6 million).

He claimed that his younger brother concealed the bulk of group stocks, which their late father and Samsung founder Lee Byung-chull held under borrowed names.

CJ Group claimed closed-circuit television footage showed Kim circling the residence of Lee in central Seoul in different cars, accusing him of obstructing its chairman's official duties.

Officials at the Jungbu Police Station said they asked why Kim had roamed around the CJ Group chairman's house and whether he attempted to shadow him.

CJ Group also claimed that Samsung Group was behind the surveillance, while Samsung officials denied any link to the Samsung C&T employee's tailing of the CJ Group chairman.

CJ Group separated from the larger Samsung Group in 1994 after control of the conglomerate passed to Lee Kun-hee. Industry insiders said the rift between the two groups still runs deep.