The houses of Sri Lankan MP Sanath Nishantha and a former minister Johnson Fernando were attacked by the protesters and set on fire on Monday as anti and pro-government protesters clashed in the country amid a nationwide curfew.
Besides, Sri Lanka Podujana Peramuna (SLPP) MP Amarakeerthi Athukorala and his personal security officer were killed in the clashes.
The lawmaker was surrounded by anti-government groups at the north western town of Nittambuwa, the police said.
The people said that gunfire came from his SUV, and when the angry mobs toppled the car, he fled and took refuge in a building and committed suicide by pulling his own revolver.
By the time he killed himself, thousands of people had surrounded the building.
Later, the lawmaker and his personal security officer were found dead, the police said.
The whole country erupted in violence after mobs supporting Mahinda Rajapaksa, who resigned as the Prime Minister, attacked peaceful protesters.
The public turned their wrath on the pro-Rajapaksa supporters as they were leaving the capital back home.
Their vehicles were stopped and attacked in most towns.
Mahinda Rajapaksa, 76, resigned hours after his supporters attacked anti-government protesters outside President Gotabaya Rajapaksa's office, leaving at least 174 people injured and prompting authorities to impose a nationwide curfew and deploy army troops in the capital.
Sri Lanka is currently in the throes of unprecedented economic turmoil since its independence from Britain in 1948. The crisis is caused in part by a lack of foreign currency, which has meant that the country cannot afford to pay for imports of staple foods and fuel, leading to acute shortages and very high prices.
Thousands of demonstrators have hit the streets across Sri Lanka since April 9 seeking resignation of President Gotabaya and Prime Minister Mahinda, as the government ran out of money for vital imports; prices of essential commodities have skyrocketed and there are acute shortages in fuel, medicines and electricity supply.
(With PTI inputs)