DALLAS (AP) — A Houston man is joining two North Texans in federal prison after what prosecutors called a diamond investment scheme that defrauded victims out of more than $6 million.

A federal judge in Dallas sentenced Christopher Arnold Jiongo on Tuesday to 46 months — almost four years — in prison and ordered to pay almost $3.8 million in restitution after pleading guilty to a wire fraud count.

Earlier this month, Craig Allen Otteson of McKinney was sentenced to 10 years in prison and Jay Bruce Heimburger of Dallas drew an eight-year prison term for their guilty pleas to mail fraud. Each of the two also must repay $4.7 million.

Investigators say more than 70 investors were scammed out of $6.4 million linked to buying and reselling diamonds on the international market.