Investigative sources said Monday that, prior to his arrest, a factory worker suspected of lacing frozen food with pesticide at a factory in the town of Oizumi, Gunma Prefecture, described to police how such an act could be carried out.

Toshiki Abe, 49, was arrested Saturday after he and every other worker employed at the Aqlifoods Co. factory at the center of the food poisoning scandal was questioned. Aqlifoods is a subsidiary of Maruha Nichiro Holdings Inc.

After his arrest, Abe told police he did not recall committing the act he described.

Police are scrutinizing his statements and questioning other employees who worked with him on the factory’s pizza production line. Abe was employed as a contract worker.

On Monday, Ota police station handed Abe over to the Maebashi District Public Prosecutors’ Office on suspicion of poisoning food products.

Before his arrest, Abe explained to investigators how somebody could poison food at the plant without admitting that he might be the culprit, according to police.

Abe’s colleagues said he had told them that anyone at the plant could carry out the act if determined to do so. Colleagues also spotted him frequently checking his cellphone for news about the food poisoning cases.

According to workers at the plant, Abe had complained of the way he was being treated at the plant, saying his work was not properly evaluated and that his bonus was cut last year.

Since he was seeking to be promoted to group leader so he could be hired as a regular employee, police suspect his discontent with the company’s managers may be behind the case.

Several of the frozen food products made by the plant were laced with the widely used insecticide malathion, which has a gasolinelike odor. The police questioned about 300 workers at the plant on Jan. 4.

Abe disappeared following his shift on Jan. 14 and police found him at a parking lot in Satte, in neighboring Saitama Prefecture, on Friday night before taking him into custody.

More than 2,800 people reported falling ill in possible connection with the poisoning, according to the Health, Labor and Welfare Ministry.