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The son of a man killed in a 1975 NYC bombing wants convict kept behind barsby Sara A. Carter

WATCH: Bombing victim's son doesn't want Obama to grant clemency to prison convict         

Joseph Connor says he wants justice for his father

Joseph Connor was 9 years old when his father, Frank Connor, was killed in a bombing at a restaurant in New York City.

That was 1975.

Now, more than 40 years later, Connor is asking President Obama not to grant clemency to one of the people accused of being involved in the deadly attack.

Oscar Lopez Rivera is the man Connor doesn't want set free. The 73-year-old was convicted of "seditious conspiracy" and sentenced to 55 years in prison in 1983. Another 20 years was added for attempting to escape after his arrest.

"My dad was 33 years old when he was murdered," said Connor, who recalled the day his father, along with four others, was killed while having lunch in Manhattan in January 1975.

"The FALN claimed responsibility for the bomb," said Connor, who recalled his mother had planned a birthday dinner on the day his father was killed.

"They claimed that they were looking for freedom for the Puerto Rican people, from the United States, when only less than 5 percent of Puerto Ricans ever voted to be free of the United States."

From the 1970s until the mid 1980s, the Puerto Rican  nationalist group known as the Armed Forces of National Liberation --or FALN --sought independence for Puerto Rico from the U.S. mainland.   

The group, which was said to have received financial support from the Cuban regime under Fidel Castro, is accused of at least 120 attacks in the U.S. that killed six and wounded more than 130 others.  

The effort to free Oscar Lopez Rivera

Some activists see Lopez Rivera as a folk hero who is being unjustly imprisoned, and in early December a group from Puerto Rico delivered a letter with 100,000 signatures asking for clemency for Lopez Rivera.

And there are some well-known people asking Obama for Lopez Rivera's release. 

Award-winning playwright Lin-Manuel Miranda, of the Broadway hit show Hamilton, personally visited Obama at the White House to ask for Lopez Rivera's release. But Connor called Miranda a hypocrite, saying "Hamilton said that no president would ever abuse the pardon power because he'd be thought conniving, or having connivance." 

Nobel Peace Laureate Archbishop Desmond Tutu, former Democratic presidential candidate Bernie Sanders  and the AFL-CIO, among others, have also asked for clemency for Lopez Rivera. 

Lopez Rivera turned down clemency offer from President Clinton

Former President Bill Clinton offered a controversial clemency to 16 convicted FALN members in 1999, but Rivera turned it down, reportedly because he would not accept clemency unless it was extended to other FALN members still behind bars.

"He was the captain willing to go down with his ship," Connor said. "All I'm looking for is justice. I'm not asking him to spend a second in prison more than he was sentenced to." 

The effort to keep Lopez Rivera in prison

But the families of the victims, former FBI officials involved in the case, and those wounded by FALN bombings have alsosent a letter to Obama opposing his early release. 

Are there FALN fugitives in hiding?

"There's about 70 fugitives that are in Cuba...I'm looking for the Trump administration to make that a condition of normalization if we're going to move forward at all with Cuba." 

You can follow Sara A. Carter on Twitter @SaraCarterDC.