Alan Gross Freed, What About Other Americans Held Abroad?

American contractor Alan Gross arrived in the U.S. today after being held in a Cuban prison for five years, the culmination of more than a year of secret back-channel talks between the Cuban and American governments.

The release of Gross, 65, was announced today ahead of a historic effort to "normalize" relations between the U.S. and the small island nation just 90 miles south of Florida.

Gross was arrested in December 2009 while he was working for Development Alternatives, Inc., a contractor that had recently won a USAID grant to promote democracy and advance internet access abroad. The Cuban government, however, claimed he was spying for the U.S. and Gross was convicted on espionage charges in 2011.

His health reportedly declined recently while in custody.

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Back on U.S. soil, Gross was met by his wife and a number of high-level politicans, with hugs all around.

But such a joyful return is still a dream for several Americans being held in countries around the world. What follows are some of their cases.

If you know anything about Gross' case or those that follow, you can send a tip into the Investigative Unit tip line by CLICKING HERE.

Robert Levinson, Former FBI Agent, Kidnapped in Iran

Earlier this year Robert Levinson, a 66-year-old former FBI agent, recently broke a record no one wants to break: He became the American held abroad for the longest time, now more than seven years.

Levinson disappeared from Iran's Kish Island in 2007. While it's unclear who originally grabbed Levinson, U.S. officials have said they suspect that the Iranian government at the very least knows where he is. The Iranians, for their part, have offered to help find the former FBI agent.

Levinson's presence in Kish was something of a mystery until last December, when his family acknowledged that he was involved as a private contractor in a mission for what turned out to be rogue elements of the CIA.

READ MORE: Family of Robert Levinson Says He Was Spying for the CIA

Amir Hekmati, Former US Marine, Detained in Iran

Amir Hekmati was not kidnapped, but arrested in Iran in the fall of 2011 and appeared on Iranian state television weeks later "confessing" to being a spy for the CIA - a charge both his family and the U.S. government strongly deny. Hekmati's family said he was traveling to Tehran to visit his grandmothers.

"My son is no spy. He is innocent. He's a good fellow, a good citizen, a good man," said Ali Hekmati, Amir's father, told ABC News shortly after the broadcast. "I am absolutely afraid to death... I don't know what they're going to do with him."

Military records provided by the Marines show the Arizona-born Hekmati joined the service in 2001 after high school and served as a rifleman until he completed his service in 2005. The records show he never received military intelligence training, despite Iranian allegations otherwise.

An Iranian court initially sentenced Hekmati to death, but that decision was later overturned. Since, Hekmati's fate has been in limbo.

READ MORE: Father of American 'Spy' Calls Iranian Claims 'Bunch of Lies'

Saeed Abedini, American Preacher, Detained in Iran

In December 2013, the wife of American preacher Saeed Abedini, 33, challenged President Obama over Iran and his detention there.

"My husband is suffering because he is a Christian. He's suffering because he's an American... Yet his own government did not fight for him when his captors were across the table," Naghmeh Abedini said then, referring to nuclear negotiations held earlier. "Iran is curious: How strong is our American president? How serious is he about our American security? Would he act with firm resolve to protect and defend?"

Naghmeh's husband, Saeed, who lived in Idaho, had been setting up Christian churches in Iran for nearly a decade when he was suddenly arrested in 2012 "on charges related to his religious beliefs," according to the State Department. Naghmeh told lawmakers that her husband had since been subjected to torture and was told that he'd be set free if he converted to Islam.

READ MORE: Wife of US Pastor Held in Iran Says Obama Is Being Tested

Warren Weinstein, Community Contractor, Kidnapped in Pakistan

Just months after his boss, Osama bin Laden, was killed by U.S. Navy SEALs, the new leader of al Qaeda, Ayman al-Zawahiri, released an audio message attempting to reassure his followers, including those in American custody.

"I tell the captive soldiers of al Qaeda and the Taliban and our female prisoners held in the prisons of the crusaders and their collaborators, 'We have not forgotten you and in order to free you we have taken hostage the Jewish American Warren Weinstein,'" says Zawahiri in the 30-minute statement, which appeared on jihadi websites.

Weinstein, 72, was working as a consultant in Lahore, Pakistan, helping with community projects, when gunmen stormed his apartment and took him captive in 2011. Eventually, he was taken, or traded to al Qaeda.

"I wanted to die right there on the spot," Weinstein's wife, Elaine, told "Good Morning America" in December 2013 after seeing a new video of her husband, "because he has no idea how hard we've tried to get him back... and it's just heartbreaking because he's asking for help and I can't give him any."

At the time of Elaine's "GMA" appearance, State Department spokesperson Marie Harf told reporters the U.S. was working "behind the scenes" to try and secure Weinstein's release.

READ MORE: US Working 'Behind the Scenes' for Al Qaeda Hostage Release, State Says

Armando Torress III, Ex-Marine Kidnapped in Mexico

Former Marine Armando Torress III was kidnapped in Mexico in May 2013. At the time FBI officials said Torres drove across the International Port of Entry Bridge at Progresso, Texas, to visit his father's ranch when armed gunmen grabbed him.

The FBI told ABC News today there is no new information indicating Torress' current condition.

Caitlin Coleman, Held By Taliban

After the controversial release of Army Sgt. Bowe Bergdahl from Taliban captivity this summer, another American family stepped from relative secrecy to call on officials to bring its loved ones -- including a newborn baby -- home from the clutches of the same militant group.

Today the family of American Caitlin Coleman publicized two videos, in one of which Coleman says she and her Canadian husband, Joshua Boyle, are "prisoner[s] of the Taliban."

"I would ask that my family and my government do everything they can to bring my husband, my child and I to safety and freedom," Coleman says in the video, which was first reported by The Associated Press.

The couple disappeared while traveling through Afghanistan nearly two years ago while when Coleman was pregnant. She has since had the child in captivity, the AP reported.

The videos reportedly were first emailed to Coleman's father last July and September by an Afghan man who, as the AP put it, "identified himself as having ties to the Taliban."

Since then, Coleman and her husband have faded from the headlines. The State Department did not immediately return a request for comment on Coleman's current situation.