OSAKA -- Public prosecutors on Monday demanded that the Osaka District Court sentence a 56-year-old unemployed man to five years in prison for allegedly attempting to blackmail Santen Pharmaceutical Co., Japan's leading eyedrops maker, by threatening to put alien substances in its products.

Takeshi Maeda "has committed an extremely malicious crime," a prosecutor told the court, saying the Osaka-based drugmaker sustained 1.5 billion yen in damages, mainly due to the cost of recalling all its eyedrops and disposing of them.

The defendant, from Kadoma, Osaka Prefecture, allegedly sent the company a bottle of Santen eyedrops contaminated with benzine along with a letter demanding 20 million yen that prosecutors say Santen received June 14.

The company announced the recall of 2.5 million bottles of eyedrops on the night of June 15 after the blackmailer failed to show up to receive the 20 million yen, prosecutors said.