CHUNCHEON, South Korea, Oct. 10 (Yonhap) -- A local court here on Monday sentenced a 45-year-old South Korean man to 20 years in prison for killing his Cambodian wife last year to collect US$1 million from insurance policies.

The defendant, identified only by his surname Kang, was indicted in March last year on charges of setting his home ablaze after drugging his 23-year-old Cambodian wife with sleeping pills, causing her to suffocate to death, in Chuncheon, about 85 kilometers east of Seoul.

Kang, who wed his wife in 2008, had taken out six life insurance policies in 2010 alone under her name, which guaranteed a combined 1.2 billion won (US$1.02 million) payout in the event of her death, according to prosecutors. He had paid 420,000 won in monthly insurance premiums despite living on state subsidies, they added.

"The heavy punishment is inevitable as he premeditated the murder of his young wife carefully." said Kim Hyung-hoon, the presiding judge of the Chuncheon District Court. "His inhumane acts would cause serious social and international troubles under the circumstances in which multicultural families have increased nationwide."

The number of international marriages in South Korea has nearly tripled over the past decade, rising to 34,235 last year, compared with 11,605 in 2000, according to government data.

Government tallies show that most of the matches are between Korean men living in rural villages and women from Southeast Asian nations.