The raided gaming company operates pachinko parlours, a highly popular form of legal gambling in Japan.

Japanese authorities raided the headquarters of a gaming arcade operator on Thursday as part of a bribery investigation centred on a governing party politician, local media reported, widening a scandal that could undermine government efforts to develop casinos.

The Tokyo-based firm was under investigation for possible ties to politician Tsukasa Akimoto, who was arrested on Wednesday on suspicion of accepting bribes when he oversaw the government’s policy on casino development, broadcaster NHK said.

Without identifying the gaming company that was raided, NHK said its accounts were being scrutinised for any transactions involving Akimoto, who in the past served as a consultant for a firm that had dealings with the pachinko operator.

Pachinko, a cross between a slot machine and pinball, is a form of gambling and a national obsession, though the number of players is declining as younger generations prefer to play games on their mobile phones.

Following Akimoto’s high-profile arrest, Japanese media reported that prosecutors have been expanding their investigation into whether he accepted cash and gifts from 500.com, an online gambling operator based in China interested in developing a casino in Japan.

Prosecutors have not named the company.

Akimoto is accused of receiving about 3 million yen ($27,384) in cash and a family holiday from officials at 500.com’s Japanese subsidiary, according to media reports. He has denied any wrongdoing.

The company did not respond to multiple requests for comment, the Reuters News Agency reported.

Prosecutors have arrested three other people suspected of bribery and raided the offices of two other ruling Liberal Democratic Party (LDP) politicians in connection with the case, media reported.

While Japan’s top government spokesman insisted that Akimoto’s arrest would not delay its plans to develop three casino resorts, the investigation will likely raise questions about the bidding process.

Laws to legalise casinos in Japan have been met with public opposition because of concerns about gambling addiction.

Las Vegas-style casino resorts are among Prime Minster Shinzo Abe’s plans to attract foreign tourists.

Japan, which has a shrinking population and economy, is desperate to maintain growth in tourism, particularly after the Tokyo Olympics next year.

Some analysts have said the casino market could be worth about $20bn a year or more, thanks to an affluent population and the proximity to Asia’s wealthy gamblers.

Analysts say Akimoto’s arrest may add to the negative images that many Japanese people have of casinos, and also weigh on Abe, who is fighting allegations of using party funds to entertain supporters, lowering his public approval rating.

This story was originally published by Al Jazeera. You can view the original version here.