By Mark GuarinoCHICAGO (Reuters) - When he heard that United States and Cuba plan to restore diplomatic ties, retired New York City police detective Tom Nerney says he was struck with hope that a convicted killer he helped bring to justice but who escaped to the Caribbean island would finally be brought home after more than 30 years."It's a ray of sunshine for us," he told Reuters.Nerney and other law enforcement officials say they want the Obama administration to push Cuba to extradite the nearly 80 fugitives from the U.S. justice system who the FBI says have sought and found asylum there."It's a haven for fugitives," Nerney says of Cuba. "Hopefully [the U.S. State Department] will work something out so we can get these fugitives back."Cuba has regularly returned U.S. fugitives since 2006, but U.S. authorities say dozens remain.In a major policy shift, President Barack Obama announced on Wednesday that the United States is renewing the diplomatic ties it severed with communist-ruled Cuba in 1961.He also eased restrictions on some commerce and travel, and said he had instructed the State Department to review Cuba's current designation as a state sponsor of terrorism. The designation is in place in part because Washington says Cuba harbors fugitives wanted by the United States.The State Department has not said if it will make a priority of seeking extraditions of fugitives.The most prominent case is Joanne Chesimard who was discovered to be living in Cuba in 1984 after escaping a New Jersey state prison following her life sentence conviction for killing a New Jersey State trooper in 1973. She has since changed her name to Assata Shakur and has become an author and radical activist.Last year Chesimard became the first woman on the FBI's Most Wanted Terrorists list, with a $1 million reward posted for her capture. Newark FBI Special Agent in Charge Aaron Ford said on Wednesday there was an active arrest warrant for Chesimard and his field office was actively working the case with law enforcement partners."The FBI will continue to pursue justice, regardless of how long it takes, and are hopeful any changes in relations between the United States and Cuba will assist us with her apprehension and return," he said.In 2005, then President Fidel Castro said of the U.S. authorities' portrayal of Chesimard, "They wanted to portray her as a terrorist, something that was an injustice, a brutality, an infamous lie."In the two countries' long hostile relations, Cuba has charged in the past that the United States turns a blind eye to people Havana views as terrorists, in particular Cuban exiles suspected of involvement in attacks on Cuba.Like Chesimard, many of the best-known fugitives known to be in Cuba have been there for several decades, have established new families and made it clear through media interviews they don't expect to return home.They include Charlie Hill, an Illinois native who is wanted by New Mexico authorities for allegedly killing a state trooper and hijacking a plane in 1971. Hill escaped to Cuba with two co-defendants who have since died.Some lawmakers worry that many of the fugitives are aging fast, and that the window to get them back to the United States is now. In reference to the Chesimard case, U.S. Representative Rodney Frelinghuysen of New Jersey said in a statement Wednesday that Cuba is harboring a killer.Legal experts say extradition is a diplomatic not legal issue."Whoever has possession of the individual has control," says Barry Slotnick, a New York criminal defense attorney. "It's up to the Castro brothers," he said, referring to President Raul Castro and his older brother, Fidel Castro, who handed over the presidency in 2008.(Writing by Mark Guarino; Editing by Frances Kerry)Join the conversation about this story Click here to read full news..