Police on Thursday questioned Welfare Minister Haim Katz (Likud) for a third time as a criminal suspect in an investigation into alleged corruption at Israel Aerospace Industries.

Katz served as head of the IAI workers’ union for over two decades before becoming a minister two years ago.

The interrogation at the headquarters of the Lahav 433 anti-corruption unit in the central city of Lod was the third time Katz was questioned under caution by police in connection to the affair.

Suspicions of corruption, fraud and breach of trust at IAI became public in March when police raided the defense contractor, arresting 14 people — among them Katz’s son Yair.

The younger Katz, 36, who serves in the senior management of IAI and has been a member of its powerful workers’ union for four years, was arrested at the time on suspicion of coercing employees into joining his father’s Likud party.

He was held along with fellow union member David Peretz and their homes were raided and searched.

Yair Katz (L), son of Welfare Minister Haim Katz (Likud), at a remand hearing at the Rishon Lezion Magistrate's Court, March 22, 2017. (Flash90)

Yair Katz (L), son of Welfare Minister Haim Katz (Likud), at a remand hearing at the Rishon Lezion Magistrate’s Court, March 22, 2017. (Flash90)

The labor union at IAI, which employs some 16,000 people and is Israel’s largest state-owned company, is seen as closely tied to the senior Katz.

Responding to the attorney general’s decision in March to allow police to question Katz, the minister said that he and others and the IAI were the targets of an “unjustified smear campaign.”

“I will cooperate fully with the investigation and I am sure that everything will return calmly to the way it was before,” he said in a statement.

In a separate case, the Israel Securities Authority is investigating suspicions that Haim Katz — after being appointed a minister — bought shares in a real estate company shortly before the company announced it was merging with the Airport City business park in summer 2015. Together with another suspected insider dealer, he is thought to have illegally reaped a NIS 290,000 ($75,000) profit.

Times of Israel staff contributed to this report.