Opposition leaders Sam Rainsy and Kem Sokha joined dozens of monks and hundreds of supporters on Monday for a Pchum Ben ceremony at the memorial stupa in Phnom Penh honoring the 16 people who were killed by a grenade attack on an opposition rally in 1997. “We meet here today to offer food to the spirits of ancestors and patriots who resisted in the name of freedom. We continue to demand justice, especially for the heroic demonstrators who died during the grenade attack,” Mr. Rainsy said.