Chinese police said Tuesday that a Coca-Cola yogurt drink that killed a boy last month was deliberately laced with pesticide ingredients and was not contaminated at the soft drink maker's factory.

The announcement was made a day after the China National Center for Food Quality Supervision and Testing released its findings on the test of the Minute Maid Pulpy Milk drank by the victim, his mother and two other residents of Changchun in Jilin province on Nov. 28, as well as others in the same batch as the poisoned milk.

Police said samples taken from the problematic drinks contained Methomyl and thiodicarb -- substances used in pesticides, according to Shanghai Daily. But samples from the other yogurt drink in the same batch tested negative from the toxic substances.

Coca-Cola (KO: NYSE) released a statement Tuesday saying that its products are safe and reliable.

The mother of the poisoned boy is now in stable condition at a hospital. The other victims were treated and discharged from a hospital.

A team from the Ministry of Public Security is still investigating how the toxic substances were mixed in the yogurt drink.

It was the second incident of a Coca-Cola drink poisoning in China. In 2009 and 2010, a Sprite softdrink containing mercury poisoned two people. Results of the investigation of the incident showed the drink were also deliberately poisoned.

A Minute Maid Pulpy Milk.