A 77-year-old retired pastor from Dresden snared in a “romance scam” was released from a Spanish prison and has returned to the U.S.

“It is wonderful news that (Joseph Bryon) Martin has finally been released from prison and will be reunited with his family,” Sen. Susan Collins of Maine, one of the legislators who called for his release, said in a statement Monday.

Martin, who is staying with his son in Las Vegas, had been in a Spanish prison since July 2015, serving a six-year sentence. In March, Collins and eight of her Senate colleagues had asked Secretary of State John Kerry to negotiate his release.

Officials say Martin was one of more than 100 Americans over the age of 60 who were duped into serving as drug mules for international criminal enterprises.

Martin was arrested and sentenced in January after Spanish customs and border agents found him in possession of 1.4 kilograms of cocaine. The drugs were concealed in real estate documents that Martin had agreed to pick up in South America and was trying to deliver to a woman he had fallen in love with online.

The “romance scam” typically can take months or years to develop. Collins said the con artists develop personal relationships, usually online, with the unsuspecting individual. Sometimes, seniors are told they have won a “free” trip as part of a sweepstakes. The criminals then give them packages with sealed contents to carry across international borders.

“This scam, which preys on seniors’ emotions, is undoubtedly one of the worst scams my committee has uncovered,” said Collins, the Republican chairwoman of the Senate Special Committee on Aging. “It is outrageous that the individuals who perpetrate these crimes against seniors like Mr. Martin are free, likely targeting more unsuspecting people, while the victims languish in foreign prisons, thousands of miles from their families.”

Martin’s son, Andy Martin of Nevada, told the Aging Committee in February that his father met a woman named Joy online about six years ago. The elder Martin became infatuated with the woman, who told him she loved him.

“On behalf of myself and our family, I want to thank Senator Collins and her staff for leading the effort to gain my father’s early release,” Andy Martin said in a statement Monday. “I am blown away by the level of commitment the senator and her staff showed my father and our family throughout this ordeal.”

He also thanked U.S. Embassy officials in Madrid who visited Martin in prison, the family lawyer, and the Spanish government for the early release.