New Jersey officials hope the thaw in diplomatic relations between the US and Cuba will make it easier to extradite a former Black Panther Party member convicted of killing a state trooper in a controversial 40-year-old case.

Joanne Chesimard, who changed her name to Assata Shakur, was convicted in the 1973 death of New Jersey state trooper Werner Foerster. Prosecutors say Shakur killed Foerster in a shootout after she and two Black Panther affiliates were pulled over for allegedly driving with a broken taillight on the New Jersey Turnpike.

Two years after her conviction, in 1979, Shakur escaped from prison with the assistance of Black Liberation Army members. She resurfaced in Cuba in the 1980s, and Fidel Castro granted her asylum there.

Despite the conviction, many point to irregularities in Shakur’s case, including evidence that her attorneys’ offices may have been bugged and searched, and potential bias among the jurors. Shakur has maintained her innocence.

Shakur was rapper Tupac Shakur’s step-aunt and godmother.

Both federal and state authorities have sought Shakur’s extradition for years, even adding her to the FBI’s Most Wanted Terrorists list in 2013 and offering $2m in return for information on her. She is the first woman to be added to the list, and only the second domestic terrorist, the FBI has said.

“We remain ever hopeful in our resolve to bring Joanne Chesimard to justice,” said Paul Loriquet, a spokesperson for the New Jersey attorney general’s office. He said his office is working closely with federal authorities to secure Shakur’s “rightful place in a New Jersey prison”.

“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,” FBI special agent Aaron Ford said in a statement. He declined to give interviews on the subject.

Lennox S Hinds, Shakur’s attorney and a criminal justice professor at Rutgers University in New Jersey, could not be reached for comment.

The US has no extradition treaty with Cuba. The agreements typically require negotiation by the secretary of state, two-thirds approval from the Senate and ratification by the president.

The US State Department and the Department of Justice did not immediately return calls seeking comment about whether alternative ways to extradite Shakur might exist as a result of the change in diplomatic status.