Two janitors were arrested in the attempted sabotage of the helicopter of an Indian billionaire, a senior police official said Monday, describing the tampering as part of an internal dispute at the company that maintained the aircraft.

The investigation into the sabotage against Anil Ambani, an industrialist embroiled in a bitter and public feud with his brother, took a dark twist last week with the death of the technician who discovered the pebbles and soil in the gear box. Police ruled that death a suicide but the man's family say they suspect foul play.

The mystery has gripped Mumbai, with each new development splashed across newspapers and played in endless loops on local television channels.

Mumbai's Joint Commissioner of Police Rakesh Maria said two employees of Airworks, the company that maintained the chopper, sabotaged the gear box on April 23. Maria told reporters the potentially lethal tampering was not motivated by corporate rivalry, but was part of a dispute between Airworks employees and management dating back to 1995.

"It appears this is a problem between management and the union," Maria said. "This is probably the fifth such incident at the Airworks company," he added.

Uday Warekar, 42, and Palraj Ganpat Tewar, 38, face life in prison for violating the unlawful activities act and the civil aviation act, Maria said. They have not yet been charged.

Ambani — who heads the Reliance-Anil Dhirubhai Ambani Group, a sprawling conglomerate with interests in finance, infrastructure, power, and entertainment, among others — is one of India's richest industrialists. He has been locked in a battle with his estranged brother for years.

The industrialist's father, Dhirubhai, was one of India's first great capitalists. He launched the family empire trading in spices and textiles before going public in 1977. When he died 25 years later, the conglomerate was one of India's largest private sector groups with interests in petrochemicals, plastics, oil refineries and more.

Dhirubhai's two sons — the staid elder brother Mukesh and younger, flashier Anil — inherited the sprawling conglomerate and promptly began feuding.

Their mother finally intervened, dividing the empire between them, but the high-profile battles continue.

Mukesh, who is worth $19.5 billion, came in at seventh place on Forbes' list of the world's richest people, while Anil, with $10.1 billion, was 34th on the list.