A day after a former police officer involved with drugs went on a killing spree in Thailand that left two dozen preschoolers dead, calls are mounting for a national crackdown on the cartels that traffic billions of dollars of illicit substances a year.

Former Prime Minister Thaksin Shinawatra urged the government to ¡°speed up the suppression of drugs, especially methamphetamine tablets.¡± The former prime minister, who is in self-imposed exile, led a yearslong anti-drugs war in the early 2000s in which about 2,500 people were killed.

The perpetrator of Thursday¡¯s massacre, Panya Kamrab, had been dismissed from the police force after being arrested for illegal possession of drugs in January. He was due to attend court on Friday. Thirty-six people died in the knife and gun attack that started at a day care center in Nong Bua Lamphu province, near the Laos border, before he took his own life.